The New York Times describes the abuse of an exception to search and seizure rules at the "border" to examine the electronic devices of persons (including citizens) entering or reentering the United States. From the article:
Courts have largely supported the government’s authority to search electronic devices when travelers, including citizens, enter the United States. The so-called border search exception to the Fourth Amendment is based on the government’s interest in thwarting illegal activities.
But in March, the Court of Appeals for the Ninth Circuit in California set a new limit on device searches at the border, ruling in United States v. Cotterman that reasonable suspicion of criminal activity was required for a forensic search of a device — for instance, using software to analyze encrypted or deleted data, as opposed to performing a more cursory look at documents, photos or other files.
Customs and Border Protection, part of the Department of Homeland Security, said that it conducted electronic media searches on 4,957 people from Oct. 1, 2012, through Aug. 31, 2013, or about 15 a day, which is similar to the average during the previous two years. About 930,000 people are screened daily by border agents.
But for those pulled aside for a secondary inspection (about 35,000 travelers a day), the experience can be distressing, resulting in a missed connecting flight, a prolonged interrogation, and in Mr. House’s case, the loss of a laptop necessary for his livelihood.
... For now, the law remains murky about any limits on intrusive border inspections, including how long travelers can be detained, whether they are required to provide passwords for their devices — Mr. House refused — and whether they must answer any question an agent asks. Responses may be recorded in a traveler’s TECS file and shared with other government agencies.