[996] CLIFTON, Circuit Judge:
John Seljan appeals his conviction and sentence for multiple offenses primarily involving sexual misconduct with young children in the Philippines. Federal agents investigated Seljan after customs inspectors, conducting routine searches at a FedEx facility for unreported currency and other monetary instruments in packages being sent to foreign destinations, discovered sexually suggestive letters in packages sent by Seljan. Seljan appeals the district court’s denial of his motion to suppress all evidence resulting from those searches, primarily contending that the Fourth Amendment prohibited the inspectors from examining personal correspondence without a warrant, or from doing so after they should have realized that the document being examined was not a monetary instrument. Seljan also challenges his sentence. We affirm.
I. Facts and Procedural History
Seljan sent packages from Southern California to the Philippines via FedEx on at least three separate dates: November 20, 2002, August 2, 2003, and September 26, 2003.1 Seljan understood that the packages had to “clear customs” before leaving the United States. Affixed to each package was an international air waybill completed and signed by Seljan. A portion of the form labeled “Required Signature” stated, “Use of this Air Waybill constitutes your agreement to the Conditions of Contract on the back of this Air Waybill.” These conditions included the following provision: “Right to Inspect. Your shipment may, at our option or at the request of governmental authorities, be opened and inspected by us or such authorities at any time.”
FedEx routes international packages sent from Southern California through the company’s regional hub in Oakland, California, one of four FedEx regional sorting facilities in the United States. At that facility, FedEx sorts packages by destination and places all document-sized packages bound for a particular country into locked containers. If a package is inspected by U.S. Customs,2 its agents do the inspection prior to the placement of the packages into the container. Once loaded into a container, a package is not removed until it arrives in the destination country, in this case the Philippines.
When Seljan’s first package passed through the FedEx facility in Oakland on November 21, 2002, customs inspectors were searching packages bound for the Philippines as part of an outbound currency interdiction operation. The operation was aimed at detecting violations of 31 U.S.C. § 5316, which prohibits export or import of undeclared currency or other monetary instruments worth more than $10,000. As will be discussed in more detail below, customs inspectors are authorized under 31 U.S.C. § 5317(b) to open and inspect packages at the border to enforce that statute.
The FedEx package sent by Seljan was opened and examined as part of that operation. It was found to contain two envelopes and return address labels for Seljan’s post office box. The first envelope contained a $100 bill in U.S. currency and a pamphlet for a hotel in Bangkok. The [997] second contained a 500 peso note in Philippine currency and a short letter. That letter was typed on one side of a single sheet of paper, at the top of which was a cartoon figure. The letter contained sexually suggestive language and appeared to be addressed to an eight-year-old girl.3 Customs officials photocopied the package’s contents before returning it to FedEx for delivery.
The second package sent by Seljan was intercepted by customs inspectors at the Oakland facility on August 3, 2003, during another outbound currency operation. This package contained approximately $200 in U.S. currency, several pages of adult pornography, and two letters. One letter appeared to be addressed to the same eight-year-old girl. It was more sexually explicit than the November 2002 letter, as it expressed Seljan’s desire to engage in sex acts with the girl. The other letter was addressed to another girl’s mother and stated that Seljan would be “coming back in September .... know [redactedj’s b-Day is September 21th she’ll be XXXX 9.” [errors in original] After opening the package and seeing the pornography and letters, the customs agent alerted his supervisor, who recognized Sel-jan’s name from the November 2002 search. Again, the inspectors copied the contents and allowed FedEx to deliver the package.
An agent of the Bureau of Immigration and Customs Enforcement began to investigate Seljan. The property manager for Seljan’s former residence and one of Sel-jan’s former neighbors both told the agent that Seljan spoke of traveling to the Philippines to “have sex with kids,” that he showed child pornography, and that he had bragged about his video and scrapbook collection of similar materials. The agent determined that Seljan had traveled to the Philippines forty-three times between 1992 and 2003.
Customs inspectors at the Oakland facility stopped and searched Seljan’s third FedEx package on September 27, 2003. This package contained nine photocopied letters, $100 in U.S. currency, non-pornographic photos of Seljan with minors, and adult pornography. The letters described Seljan’s desire to engage in sex acts with the children to whom the letters were addressed. One letter was addressed to the recipient of the November 2002 letter. The inspectors copied the contents but, this time, withheld the package from delivery.
[998] Seljan arrived at Los Angeles International Airport and checked baggage for a flight to Manila on October 3, 2003. Customs agents stopped him before he boarded the plane. The agents searched his luggage, discovering adult pornographic magazines, a book of child pornography, letters written by Seljan, and fifty-two photographs of Seljan engaged in sex acts with Filipino children.
Seljan signed a Miranda waiver and made several incriminating statements. He said he had been “sexually educating” children for about twenty years, that the children’s ages ranged from eight to thirteen, and that he intended to “sexually educate” children on the trip he was there that day to take. He was not allowed to depart on that trip, however, and was placed under arrest. After his arrest, customs agents executed a search warrant at his residence and discovered adult pornography, a fiction book about pedophilia and incest, a typewriter, and various business and travel documents.
Seljan subsequently filed a motion to suppress all evidence discovered as a result of the searches of his FedEx packages. He argued that the warrantless search of these packages did not fall under any exception to the Fourth Amendment’s warrant requirement. At a minimum, he asserted, these were “extended border searches” that must be supported by reasonable suspicion. Seljan also contended that the scope of the package searches was unreasonable.
Following an evidentiary hearing, the district court denied Seljan’s motion to suppress. The district court held that inspections at the Oakland facility were “tantamount to an inspection at the international border.” Seljan, 328 F.Supp.2d at 1083. In the alternative, the district court held that Seljan had consented to these searches by agreeing to the conditions on the air waybills, and that the scope and conduct of the searches were reasonable. Id. at 1085.
At the conclusion of a three-day bench trial, the district court found Seljan guilty of one count of attempted travel with intent to engage in illicit sexual conduct in violation of 18 U.S.C. §§ 2423(b) and (e); two counts of use of an interstate facility to entice a minor to engage in criminal sexual acts in violation of 18 U.S.C. § 2422(b); one count of production of child pornography in violation of 18 U.S.C. § 2251(a); and two counts of possession of child pornography in violation of 18 U.S.C. § 2252A(a)(5)(B).
The district court imposed sentence on March 28, 2005. Citing the defendant’s age — at the time sentence was imposed, Seljan was 87 years old — the court sentenced him to 240 months (20 years) of imprisonment. That duration was 22 months shorter than the low end of the calculated Guidelines range.
Seljan filed a timely appeal. A three-judge panel of this court affirmed, with one judge dissenting in part, regarding the denial of the motion to suppress. United States v. Seljan, 497 F.3d 1035 (9th Cir. 2007). By a vote of a majority of nonrecused active judges, it was ordered that the case be reheard en banc and that the three-judge panel opinion not be cited as precedent. 512 F.3d 1203 (9th Cir.2008). Upon rehearing, we affirm the judgment of the district court.4
II. Motion to Suppress
Seljan challenges the district court’s denial of his motion to suppress all evidence [999] discovered as a result of customs inspections of the Philippines-bound packages he sent through FedEx. Seljan focuses on the first search, which occurred on November 21, 2002. He contends that the customs inspectors violated his Fourth Amendment rights when they opened the package and read the enclosed letter without reasonable suspicion that doing so would reveal contraband or uncover evidence of criminal activity. Seljan challenges the later searches as tainted fruits of this initial inspection.
The government offers two justifications for the November 2002 search. First, it defends the search as one occurring at the functional equivalent of the international border, contending that there are few, if any, limits on the government’s ability to search at the border and that this search did not run afoul of any such limitations. Second, the government contends that Sel-jan consented to the search by signing the FedEx air waybill.5
The customs search at the Oakland FedEx regional sorting facility took place at the functional equivalent of the border. United States v. Abbouchi, 502 F.3d 850, 855-56 (9th Cir.2007). It should, therefore, be analyzed as a border search.6
“The border search doctrine is a narrow exception to the Fourth Amendment prohibition against warrantless searches without probable cause.” United States v. Sutter, 340 F.3d 1022, 1025 (9th Cir.2003). Under this doctrine, customs officials may conduct searches at the international border to identify the illegal transportation of contraband or undeclared articles across the border. See United States v. Alfonso, 759 F.2d 728, 737 (9th Cir.1985). Such border searches are grounded in the government’s right to protect the nation’s territorial integrity by examining persons and property entering and leaving the country. United States v. Flores-Montano, 541 U.S. 149, 152-53, 124 S.Ct. 1582, 158 L.Ed.2d 311 (2004); see also United States v. Cortez-Rocha, 394 F.3d 1115, 1118-19 (9th Cir.), cert. denied, 546 U.S. 849, 126 S.Ct. 105, 163 L.Ed.2d 118 (2005). Because searches at the international border of both inbound and outbound persons or property are conducted “pursuant to the long-standing right of the sovereign to protect itself,” they generally require neither a warrant nor individualized suspicion. United States v. Ramsey, 431 U.S. 606, 616, 97 S.Ct. 1972, 52 L.Ed.2d 617 (1977); see also Sutter, 340 F.3d at 1025; United States v. Cardona, 769 F.2d 625, 629 (9th Cir.1985) (“The fact that this case involves an exit search does not alter our analysis. Since the border search exception applies to exit searches, there is no principled basis to conclude that the extended border search doctrine does not apply with equal force to exit searches as it does to entry searches.”).
The Supreme Court has said that “ ‘searches made at the border ... are reasonable simply by virtue of the fact that they occur at the border.’ ” Flores-Montano, 541 U.S. at 152-53, 124 S.Ct. 1582 (quoting Ramsey, 431 U.S. at 616, 97 S.Ct. 1972); see also Cortez-Rocha, 394 F.3d at 1118-19. Notwithstanding this broad language, the Court has also suggested that the Fourth Amendment might impose some limits on searches at the border, but [1000] it has neither spoken definitively on that subject nor clearly defined the limits, if any.
Most recently, in Flores-Montano, in which a warrantless border search of an automobile that included the removal and disassembly of the car’s gas tank was held lawful despite the lack of reasonable suspicion, the Court noted that there are “reasons that might support a requirement of some level of suspicion in the case of highly intrusive searches of the person — dignity and privacy interests of the person being searched.” 541 U.S. at 152, 124 S.Ct. 1582. It concluded, however, that those reasons did not carry over to protect against the search of a vehicle. Id. In the same opinion, the Court acknowledged that “it may be true that some searches of property are so destructive as to require a different result,” but held that the search in that case was not so destructive. Id. at 155-56, 124 S.Ct. 1582. The Court explicitly left open, not for the first time, the question “whether, and under what circumstances, a border search might be deemed ‘unreasonable’ because of the particularly offensive manner in which it is carried out.” Id. at 154 n. 2, 124 S.Ct. 1582 (quoting Ramsey, 431 U.S. at 618 n. 13, 97 S.Ct. 1972).
Previously, in United States v. Montoya de Hernandez, 473 U.S. 531, 541, 105 S.Ct. 3304, 87 L.Ed.2d 381 (1985), the Court held that reasonable suspicion was required to detain at the border and to search the alimentary canal of a traveler thought to have ingested balloons filled with narcotics. But the Court declined in that case to decide “what level of suspicion, if any, is required for nonroutine border searches such as strip, body cavity, or involuntary x-ray searches.” Id. at 541 n. 4, 105 S.Ct. 3304.
Prior to Flores-Montano, we held that a border search does not require “probable cause, warrants or even suspicion” and comports with the Fourth Amendment “unless it violates ‘reasonableness.’ Reasonableness, when used in the context of a border search, is ‘incapable of comprehensive definition or of mechanical application....’ The scope of the intrusion, the manner of its conduct, and the justification for its initiation must all be considered in determining whether a search comports with reasonableness.” See United States v. Duncan, 693 F.2d 971, 977 (9th Cir.1982) (internal citations omitted). The statements in Duncan and similar discussions in our other decisions may have been superseded by the Supreme Court’s decision in Flores-Montano, which reversed a decision by our court and made clear that a showing of “reasonable suspicion” was not required simply because the search in question went beyond a “routine” search. We need not make that determination, however, because there is no conflict between our precedent and the dictates of Flores-Montano with respect to the issues in this case.
We decline the government’s invitation to decide this case by holding that, at the border, anything goes. Given the acknowledgments by the Court in Flores-Montano that there might be searches that are so intrusive, destructive, or offensive that they would be deemed unreasonable under the Fourth Amendment, and the holding in Montoya de Hernandez that reasonable suspicion was needed to justify a border search and seizure as intrusive as that one, it is appropriate for us to consider the particular circumstances of this search.
The district court specifically found that Seljan’s first package was opened and examined by customs inspectors when they were conducting an outbound currency interdiction operation targeting packages bound for the Philippines, checking for violations of 31 U.S.C. § 5316. See Seljan, 328 F.Supp.2d at 1079. Based on the rec[1001] ord, that finding was not clearly erroneous.7
As noted above, section 5316 requires that a report be filed with the Treasury Department whenever a person “transports, is about to transport, or has transported” monetary instruments worth more than $10,000. The provision explicitly covers instruments transported either way— both exported from and imported into the United States. “Monetary instruments” means more than currency. The term is defined, in regulations authorized under 31 U.S.C. § 5312(a)(3), to include:
(i) Currency;
(ii) Traveler’s checks in any form;
(iii) All negotiable instruments (including personal checks, business checks, official bank checks, cashier’s checks, third-party checks, promissory notes (as that term is defined in the Uniform Commercial Code), and money orders) that are either in bearer form, endorsed without restriction, made out to a fictitious payee (for the purposes of § 103.23), or otherwise in such form that title thereto passes upon delivery;
(iv) Incomplete instruments (including personal checks, business checks, official bank checks, cashier’s checks, third-party checks, promissory notes (as that term is defined in the Uniform Commercial Code), and money orders) signed but with the payee’s name omitted; and
(v) Securities or stock in bearer form or otherwise in such form that title thereto passes upon delivery.
31 C.F.R. § 103.11(u)(l).
The customs interdiction operation was explicitly authorized under 31 U.S.C. § 5317(b), which provides: “For purposes of ensuring compliance with the requirements of section 5316, a customs officer may stop and search, at the border and without a search warrant, any vehicle, vessel, aircraft, or other conveyance, any envelope or other container, and any person entering or departing from the United States.” Id. (emphasis added); see also United States v. Gomez-Osorio, 957 F.2d 636, 643 (9th Cir.1992).
More broadly, and separate from the statutory authority for the particular inspection here, the government has the authority to search at the border “based on its inherent sovereign authority to protect its territorial integrity.” Torres v. Puerto Rico, 442 U.S. 465, 472-73, 99 S.Ct. 2425, 61 L.Ed.2d 1 (1979); see Flores-Montano, 541 U.S. at 152, 124 S.Ct. 1582; Ramsey, 431 U.S. at 620, 97 S.Ct. 1972. Every Congress since the founding of our government, including the Congress that first proposed the Fourth Amendment, “has granted the Executive plenary authority to conduct routine searches and seizures at the border, without probable cause or a warrant, in order to regulate the collection of duties and to prevent the introduction of contraband into this country.” Montoya de Hernandez, 473 U.S. at 537, 105 S.Ct. 3304; see Ramsey, 431 U.S. at 616-19, 97 S.Ct. 1972.
The government’s authority to conduct border searches is justified by its interest in regulating the flow of persons and property across the border. The government has an obvious interest in enforcing section 5316.
[1002] Seljan argues that the search, regardless of its authorization, was unreasonably intrusive in its scope because it entailed reading his personal correspondence. Sel-jan further objects to the search because he contends that it should have been clear to the customs agent, without having to read the letter, that the FedEx package contained no undeclared currency or other contraband.
The concerns identified by the Supreme Court are not present here. The search did not involve the destruction of property, it was not conducted in a “particularly offensive manner,” and it was not a “highly intrusive search[] of the person.” Flores-Montano, 541 U.S. at 152, 154 n. 2, 155-56, 124 S.Ct. 1582 (internal quotation marks omitted). There was no destruction of property. The first FedEx package, the target of Seljan’s motion to suppress, was returned to FedEx for delivery and presumably reached its destination in good order. Nor was the search conducted in an manner that could be categorized as “particularly offensive.” See Ramsey, 431 U.S. at 618 n. 13, 97 S.Ct. 1972. Ramsey suggested that a border search might be unreasonable “because of the particularly offensive manner in which it is carried out,” citing as examples searches that were held unreasonable in Kremen v. United States, 353 U.S. 346, 77 S.Ct. 828, 1 L.Ed.2d 876 (1957) (officers, without a search warrant, seized the entire contents of a cabin and took the items 200 miles away to be examined), and Go-Bart Importing Co. v. United States, 282 U.S. 344, 356-58, 51 S.Ct. 153, 75 L.Ed. 374 (1931) (Officer falsely claimed to have a search warrant and then “made a general and apparently unlimited search, ransacking the desk, safe, filing cases, and other parts of the office. It was a lawless invasion of the premises and a general exploratory search in the hope that evidence of crime might be found.”). There was nothing like that here.
The concern in this case is simply with how far the search went — whether it was too intrusive in scope. We agree with Seljan that there was intrusion into his privacy, but the degree of intrusion must be viewed in perspective. Seljan voluntarily gave the package containing the letter to FedEx for delivery to someone in the Philippines, with knowledge that it would have to cross the border and clear customs. The reasonable expectation of privacy for that package was necessarily tempered. When the Supreme Court spoke of “highly intrusive searches” in Flores-Montano, it expressly referred to “highly intrusive searches of the person” which raised concern based on the “dignity and privacy interests of the person being searched,” and made the point that this concern was not triggered by a search of the person’s vehicle. 541 U.S. at 152, 124 S.Ct. 1582. The reference in Flores-Mon-tano to “highly intrusive searches of the person” followed a discussion of Montoya de Hernandez, which involved an actual physical intrusion into a person’s body to search the alimentary canal. In the latter case, the Court illustrated its reference to “nonroutine border searches” , by citing “searches such as strip, body cavity, or involuntary x-ray searches.” 473 U.S. at 541 n. 4, 105 S.Ct. 3304. The search of Seljan’s FedEx package was substantially less intrusive than these examples.
Cases in which we have considered invalidating a border search because of the highly intrusive scope or manner of the search have dealt with only a limited number of scenarios, none quite like this one. Most have been consistent with Flores-Montano and involved highly destructive searches of property or intrusive searches of the person. Even when we have recognized the possibility that there might be a limit on the permissible scope or manner of a given search — which discussion may have been superseded by subsequent Su[1003] preme Court caselaw, as we noted above— we have usually concluded that the limit had not been exceeded, consistent with the Supreme Court’s conclusion that the government’s authority to search at the border is broad and “at its zenith.” Flores-Montano, 541 U.S. at 152, 124 S.Ct. 1582. In United States v. Ramos-Saenz, 86 F.3d 59, 61 (9th Cir.1994), we concluded that a border search goes beyond the routine “only when it reaches the degree of intrusiveness present in a strip search or body cavity search” and that the search of the defendant’s shoes in that case did not go beyond routine. In the context of vehicle searches, we have accepted the possibility that a search could conceivably be so destructive that it would exceed its reasonable scope, but have rejected arguments that the limit was exceeded in particular cases. See, e.g., United States v. Hernandez, 424 F.3d 1056, 1059 (9th Cir.2005) (dismantling internal car door panels not excessively destructive as to be unreasonable); United States v. Chaudhry, 424 F.3d 1051, 1053 (9th Cir.2005), cert. denied, 547 U.S. 1083, 126 S.Ct. 1803, 164 L.Ed.2d 540 (2006) (concluding that exploratory drilling during suspicionless vehicle search at the border was done in reasonable manner where a “single 5/16-inch hole [was] drilled in the bed of a pickup truck”). We have also considered the question of whether a prolonged detention pursuant to a suspicionless border search might be unreasonable, without finding that it was. See United States v. Gonzalez-Rincon, 36 F.3d 859, 861, 863-64 (9th Cir.1994) (holding that scope of border search was reasonable where nervous defendant arriving from Colombia was detained for several hours to monitor for bowel movements before she expelled seventy-three balloons containing cocaine).
We conclude that the customs inspection here was not overly intrusive. Even assuming that there are limits to the government’s right to search packages at the border, those limits were not transgressed in this case.
An envelope containing personal correspondence is not uniquely protected from search at the border.8 The Supreme Court effectively rejected that contention in Ramsey, when it reversed a holding of the D.C. Circuit that international letter-class mail could not be opened without a search warrant. 431 U.S. at 608, 97 S.Ct. 1972. As far as the Fourth Amendment is concerned, mailed envelopes are covered by the border search exception, just as envelopes carried on a traveler’s person are covered:
It was conceded at oral argument that customs officials could search, without probable cause and without a warrant, envelopes carried by an entering traveler, whether in his luggage or on his person.... Surely no different constitutional standard should apply simply because the envelopes were mailed not carried. The critical fact is that the envelopes cross the border and enter this country, not that they are brought in by one mode of transportation rather than another. It is their entry into this country from without it that makes a resulting search “reasonable.”
Id. at 620, 97 S.Ct. 1972. We have upheld searches of similar items at the border without warrant or particularized suspicion. See Abbouchi, 502 F.3d at 855-56 (contents of a UPS package, including a sealed envelope containing two social security cards, two permanent resident alien cards, and handwritten notes); United States v. Tsai 282 F.3d 690, 696 (9th Cir. 2002) (contents of a traveler’s briefcase and luggage); United States v. Grayson, [1004] 597 F.2d 1225, 1228-29 (9th Cir.1979) (papers in a traveler’s shirt pocket). There is no reason to protect an envelope sent via FedEx more than one that is mailed, sent by UPS, or carried in a traveler’s pocket across the border.
Seljan also argues that the customs inspectors were required to stop their examination without reading the letter. Even if the inspectors were authorized to open the FedEx package and the sealed envelopes within the package, he contends that it should have been apparent to the customs agent that the letter was not currency or another monetary instrument, such that no reading was justified or permitted.
We need not decide whether Flores-Montano forecloses this argument, because Seljan’s argument is unpersuasive on other grounds, due to the facts of his case. For one thing, the statute that affirmatively authorized the customs inspectors to open this package and envelope, 31 U.S.C. § 5317(b), does not define the limits on border searches under the Fourth Amendment. Seljan has not argued that the evidence should be suppressed because of a violation of section 5317(b), and nothing in that statute appears to have been violated in any event. Seljan has not cited authority under the Fourth Amendment that required the agents to disregard evidence of other unlawful activity, even if the unlawfulness had nothing to do with transporting unreported monetary instruments.
Moreover, the customs inspector’s task here was not so simple. Although the bills turned out to be of small denominations, both of the sealed envelopes within the first FedEx parcel did in fact contain currency, so there was reason for the inspector to pause and look more carefully. In addition, many documents in addition to currency may qualify as “monetary instruments,” as the definition reprinted above, at 15, demonstrates, and thus are subject to the reporting requirements of 31 U.S.C. § 5316. A simple sheet of paper could, for example, turn out to be a negotiable instrument, such as a promissory note in bearer form. The inspector could not determine that the folded paper found inside the envelope was not a monetary instrument without actually looking at what was printed there.
Nor did it take exceptional scrutiny of Seljan’s one-page letter for the inspector to detect possible unlawful conduct. In this case, evidence of possible pedophilia could be ascertained by a glance.
The experience of the customs agents here is instructive. The team leader for the interdiction operation stated that “[i]n inspecting [outbound] packages, Customs inspectors adopt a two-tier approach. First, they scan, not read, any documents. If something during their scan gives them reasonable suspicion to suspect a violation of the law, the inspectors give a closer inspection to the contents of the package.” Though this “scanning” protocol was not required under section 5317(b), it provided some protection against overly intrusive searches. The inspector who examined Seljan’s FedEx package testified that he adhered to the scanning protocol and that while doing so the offensive material initially became evident:
A: ... I opened up the second letter, and I scanned the letter that was in the second envelope.
Q: Did you notice anything during your scan?
A: I was reading as I was scanning. I caught a couple of sentences on there, something about an eight-year-old girl, something about “I love you,” and there was a final sentence at the bottom stating that
... “little girl’s peanuts smells like roses,” and at that time I reread the letter [1005] thoroughly to understand what the letter was saying.
His method of “scanning,” even though it included reading a few words by necessity, was not unreasonable. In contrast to the limitation on reading correspondence under 19 U.S.C. § 1583(c)(2), there is no similar prohibition under 31 U.S.C. § 5317(b), which authorized this search. Neither is there such a limitation in the Supreme Court’s Fourth Amendment cases.
We cannot reasonably expect customs officials wholly to abandon their sensory faculties when conducting inspections under the plenary authority of a border search. On the facts here, the customs inspector did not act contrary to objective reasonableness. Although he was checking for compliance with currency declaration requirements under section 5316, he did not need to read the letter carefully to detect evidence of possible pedophilia. The letter in the first paragraph suggests its author’s possibly illegal proclivities: “Yes, Honey, I like little girls like you.” The inspector was not required to disregard what he saw, even if it was not what he was there to look for. See United States v. Issacs, 708 F.2d 1365, 1369 (9th Cir.1983). We refuse to impose an unworkable and unreasonable constraint on the nation’s customs officials by requiring that they avert their eyes from obvious unlawfulness.9
We find support for our conclusion from our precedents involving the plain view doctrine. “An example of the applicability of the ‘plain view’ doctrine is the situation in which the police have a warrant to search a given area for specified objects, and in the course of the search come across some other article of incriminating character.” Coolidge v. New Hampshire, 403 U.S. 443, 465, 91 S.Ct. 2022, 29 L.Ed.2d 564 (1971) (plurality opinion), abrogated on other grounds as recognized by United States v. Ewain, 88 F.3d 689, 693 (9th Cir.1996). In United States v. Bulacan, we observed that warrantless seizures are constitutional under the plain view doctrine in situations where “the incriminating nature of the object must be immediately apparent and the officer must ‘have a lawful right of access to the object itself.’ ” 156 F.3d 963, 968 (9th Cir.1998) (quoting Horton v. California, 496 U.S. 128, 136, 110 S.Ct. 2301, 110 L.Ed.2d 112 (1990)). In that case we noted that “[t]he initial intrusion can be justified by a warrant or by one of the recognized exceptions of the warrant requirement.” Id. (emphasis added); see also Coolidge, 403 U.S. at 465, 91 S.Ct. 2022 (“Where the initial intrusion that brings the police within plain view of such an article is supported, not by a warrant, but by one of the recognized exceptions to the warrant requirement, the seizure is also legitimate.”).10
[1006] The customs inspector’s examination of the letter inside the second envelope was, similarly, not unreasonably intrusive in its scope. The inspector was authorized to open the FedEx package and the envelopes inside it. That meant he had a “lawful right of access to the object” to be searched, i.e. the FedEx package and its contents. See Horton, 496 U.S. at 137, 110 S.Ct. 2801. In the course of that authorized examination, he appropriately scanned the document and noticed the “immediately apparent” evidence of pedophilia. See Bulacan, 156 F.3d at 968. The inspector’s scanning of the document was not unreasonable. In Issacs, this court made clear that the plain view doctrine permitted “brief perusal” of a written document’s contents where the inspector was authorized to examine the document. 708 F.2d at 1370. In this case, the inspector was authorized to examine the documents to determine whether they were monetary instruments. See 31 U.S.C. § 5317(b).
The scope and manner of the search of the letter was constrained, as the letter had to be scanned when the package was opened to determine whether Seljan had violated 31 U.S.C. § 5316’s currency reporting requirements, and the evidence of pedophilia presented itself at that time. The review of the FedEx package’s contents was nothing like an intrusive body search or the dismantling of a car. The search of the FedEx package was reasonable in manner and scope.
We conclude that the inspection of the first FedEx package was not unreasonable and did not violate the Fourth Amendment. The search was justified as a border search and as an inspection under 31 U.S.C. § 5317(b), and it was not unduly intrusive in scope or manner. The motion to suppress was properly denied by the district court, and Seljan’s conviction should be affirmed.
III. Sentencing
Seljan appeals several aspects of his 240-month sentence. He first challenges the Presentence Report’s recommendation that several counts of the indictment be added up individually rather than grouped for purposes of calculating the “Multiple Count Adjustment” under the Sentencing Guidelines. He argues that the district court did not adequately consider his advanced age when imposing sentence. Finally, he contends that the district court gave undue weight to his past sexual abuse conviction, thereby elevating his criminal history category.
It is now established that “[a]ppel-late review is to determine whether the sentence is reasonable; only a procedurally erroneous or substantively unreasonable sentence will be set aside.” United States v. Carty, 520 F.3d 984, 993 (9th Cir.2008) (en banc). We conclude that Seljan’s contentions do not warrant setting his sentence aside.
A. Grouping of Counts
Seljan contends that the district court failed to group the charges in Count One (attempted travel with intent to engage in illicit sexual conduct with a minor) and Counts Two and Three (using a facility of interstate and foreign commerce to entice [1007] a minor to engage in sexual activity). The district court declined to group these offenses because it concluded that the counts involved different victims with different ages.11
Seljan’s claim that some grouping is appropriate may be correct. United States Sentencing Guidelines Manual (“U.S.S.G.”) section 3D1.2 provides that counts that “involve the same victim and two or more acts or transactions connected by a common criminal objective or constituting part of a common scheme or plan” may be grouped. U.S.S.G. § 3D1.2(b) (2002). Count One alleges attempted travel with intent to engage in criminal sexual activity with victims “Em Em” and “Janel.” Count Two alleges use of facilities of interstate and foreign commerce to entice victim “Em Em” into sexual activity, and Count Three alleges enticement of victim “Janel.” Thus, Counts One and Two share a common victim, and Counts One and Three share a different common victim.
Seljan’s attempted travel to the Philippines (alleged in Count One) and the packages sent to the victims seeking to entice them into illicit sexual activity (alleged in Counts Two and Three) arguably involve the same composite harm to each minor victim and are connected by a common criminal objective or plan. See U.S.S.G. § 3D1.2 cmt. n. 4. Thus, it may be appropriate to combine the three counts into two groups: one for the conduct against the victim common to Counts One and Two, and the other for conduct against the victim common to Counts One and Three.12
Even if Seljan is correct, however, he is not entitled to relief. Assuming the first three counts should be consolidated into two groups for purposes of applying U.S.S.G. § 3D1.4, this is only a net reduction of one unit. With one unit for Counts Six and Seven (which were grouped below) and another for Count Four, the total units for purposes of applying section 3D1.4 is four. This would still result in a four-level increase in offense level, the same amount imposed by the district court. See § 3D1.4 (prescribing a four-level increase for three-and-a-half to five units). There was no error in calculating the Guidelines range since the result would have been the same either way.
B. Advanced Age
Seljan argues that the district court did not adequately consider his advanced age. This argument is meritless. The district court acknowledged that Sel-jan’s age and health reduced the likelihood of recidivism, and it addressed Seljan’s concern that the 20-year sentence at age 87 was tantamount to life imprisonment. The district court even considered the sentence that a defendant without a prior conviction would receive. Indeed, the sentence imposed by the district court was 22 months below the low end of the Guidelines range. Seljan argues only that the reduction should have been even greater. On this record, however, the district court’s sentence was reasonable.
C. Effect of Seljan’s Prior Conviction
Finally, Seljan argues that the district court gave too much weight to the Guide[1008] lines by applying a criminal history category of V pursuant to Guidelines section 4B1.5(a)(2), which provides for sentencing of “[rjepeat and [d]angerous [s]ex [o]ffender[s][a]gainst [m]inors.”
No party seriously disputes that Seljan’s 1977 Wisconsin conviction qualifies as a “sex offense conviction” under section 4B1.5. Rather, Seljan argues that because criminal history is primarily relevant as an indicator of future recidivism, the district court should have disregarded the elevated criminal history category in light of his age and low actual likelihood of recidivism. But the district court was not permitted to ignore the prior conviction. If it had simply disregarded the prescription of section 4B1.5, it would have violated the requirement that the district court properly calculate the Guidelines range before deciding whether such a sentence is reasonable. See Carty, 520 F.3d at 991. Moreover, the court did consider the impact of Seljan’s age on his likelihood of recidivism after it calculated the Guidelines range and adjusted the sentence accordingly. Nothing in the record compels any further tinkering.
IV. Conclusion
We hold that customs officials acting under authority of 31 U.S.C. § 5317(b) may, at the functional equivalent of the border, search a package or container being shipped via FedEx across the border, without a warrant. The inspection may include smaller envelopes or other wrapped or sealed objects contained within the package. The search does not violate the Fourth Amendment simply because it may entail scanning of personal correspondence, or because the evidence of contraband or other criminal activity that is detected may not relate to the interdiction of undeclared currency. To unreasonably constrain customs inspectors from searching and seizing obviously incriminating materials would be imprudent and inconsistent with Fourth Amendment jurisprudence. We also hold that the sentence imposed on Seljan by the district court was procedurally correct and substantively reasonable.
AFFIRMED