Law360, New York (October 22, 2015, 10:56 AM ET) -- If you travel into the United States from abroad and carry sensitive or privileged information on your laptop or phone, you are at risk. If your employer is under investigation in the United States, there is a clear and present danger. This is the best argument ever for cloud computing.

Everyone knows that a federal agent cannot walk up to you as you are waiting for a cab at the airport and rifle through your papers without first obtaining a search warrant, having persuaded a judge that probable cause exists to justify such an invasion of privacy. Surely then, it would be equally wrongful if the agent were to ask a US Customs and Border Protection officer to do the same thing while you were walking between the baggage carousel and the cab stand — right? Wrong — because you were on an international flight and passed through a border zone. But surely the judicially manufactured “border search exception” to the Fourth Amendment is limited by, say, proper border purpose? Wrong again.

Last month, the Second Circuit held that customs officers could, without a warrant or probable cause, examine and copy documents belonging to a traveler who was under investigation for a crime completely unrelated to customs or border issues. The defendant in United States v. David Levy was returning home to the United States from a business trip to Panama. Levy was the subject of an ongoing investigation into alleged stock manipulation, and at the airport he was detained by CBP officers who had been asked for “assistance” by the agency investigating Levy. CBP inspected his luggage, including a notebook of handwritten jottings, which they photocopied. Less than three days later, Levy was indicted for a variety of crimes. The notebook was a key piece of evidence used to convict.

Levy brought an appeal before the Second Circuit, claiming that the duplication of the notebook was an illegal search. The judges acknowledged that it was debatable whether copying a notebook a traveler brings across the border is “routine” — a routine search does not even require reasonable suspicion, whim is sufficient. The Levy court avoided answering that question by claiming that such a search was justifiable because the customs agents had reasonable suspicion — the agents knew that Levy was under investigation for stock manipulation because they had been tipped off by prosecutors. Just to recap — the investigating agency creates the “reasonable suspicion” by telling CPB you are under investigation, then the CPB seizes the information and hands it over to investigating agency.

The Second Circuit found that it was irrelevant that the crime was completely unrelated to the crimes in CBP’s purview. But the panel anchored its reasoning in a prior DC Circuit case holding “where customs officers are authorized to search for material subject to duty or otherwise introduced illegally into the United States and they discover the instrumentalities or evidence of crimes, they may seize the same.” United States v. Gurr, 471 F.3d 144 (D.C. Cir. 2006) (emphasis added) (quoting United States v. Schoor, 597 F.2d 1303, 1306 (9th Cir.1979) (searching for narcotics CPB officers found records reflecting scheme to smuggle drugs in radios).

Of course that is exactly what did not happen in Levy. The CPB was not searching for meth when Levy’s notebook documenting his schemes fell open and they happened upon the smoking gun that would secure his conviction. The only reason the notebook was “discovered” was their suspicion about stock manipulation, created by the investigating agency. And, it should be noted, in Gurr the DC Circuit was sufficiently circumspect of the searches that its final holding was simply “any error in admitting the seized financial documents was harmless beyond a reasonable doubt and a new trial is not required.”

In a world of cross-border commerce and cross-border criminal investigations, Levy is hardly an oddball one-off. And anyone potentially the subject of a government investigation should be cautious about what is on their person or in their bags as they enter or exit the U.S. Although the issue in Levy was a notebook, there’s nothing to stop a customs official from examining a laptop and copying material from it or even mirroring the entire computer. See United States v. Cotterman, 709 F.3d 952, 969 (9th Cir. 2013); Abidor v. Napolitano, 990 F. Supp. 2d 260, 264 (E.D.N.Y. 2013). The erosion of constitutional protections follows a familiar path — starting in the drug, Gurr, child pornography, Cotterman and terrorism, Abidor, cases, and then the shortcuts make their way into the mainstream investigative toolkit, Levy.

But it gets worse. The official position of the US government is that the attorney-client privilege does not exist at the border. All that is required to invade a proper assertion of privilege is the OK of a customs lawyer or a US attorney:

5.2.1 Officers may encounter materials that appear to be legal in nature, or an individual may assert that certain information is protected by attorney-client or attorney work product privilege. Legal materials are not necessarily exempt from a border search, but they may be subject to the following special handling procedures: If an Officer suspects that the content of such a material may constitute evidence of a crime or otherwise pertain to a determination within the jurisdiction of CBP, the Officer must seek advice from the CBP Associate/Assistant Chief Counsel before conducting a search of the material, and this consultation shall be noted in appropriate CBP systems of records. CBP counsel will coordinate with the US Attorney's Office as appropriate.

CBP Directive No. 3340-049. Again, no neutral magistrate, no warrant, no process. Perhaps some comfort can be taken from the fact that the prosecuting attorneys pursuing the investigation that created the reasonable suspicion that produced the seizure have to sign-off on the invasion of a privilege asserted over the materials seized. Perhaps not.

And so cloud computing is the way to go. Or simply put everything in a sealed and adequately stamped envelope before you get off the plane:

(b) Only correspondence. No Customs officer or employee shall open sealed letter class mail which appears to contain only correspondence unless prior to the opening:(1) A search warrant authorizing that action has been obtained from an appropriate judge of United States magistrate, or(2) The sender or the addressee has given written authorization for the opening.

19 C.F.R. § 145.3. And no, FedEx envelopes do not count.

Anyone else think a hash has been made of the Fourth Amendment?