In these ever tense times for civil liberties, we have a new case out of the Bay Area that is likely to ruffle some privacy-protection feathers. ABC 7 brings news of a Bay Area art professor who had his phone confiscated at SFO when returning from an international trip, and that Customs and Border Protection agents searched his smartphone without a warrant and with no probable cause.

"It was an unreasonable search, there was no probable cause, there was no warrant," said the California College of the Arts professor in question, Aaron Gach, of the February 23, 2017 incident.

Customs and Border Protection declined to comment on the matter, because they call it “pending litigation”. It is pending litigation because the ACLU has filed an administrative complaint against the CBP and the Department of Homeland Security relating to the search and seizure of Gach’s phone.

“Officers told Mr. Gach his phone would be detained for an 'indeterminate' amount of time if he chose not to enter the passcode and submit to a search," the ACLU says in their complaint. "The officers also told Mr. Gach that CBP had downloaded information from the phones of other travelers who had refused to unlock their devices. When CBP officers asked Mr. Gach why he did not want to submit his phone for a search, Mr. Gach replied that he believes strongly in the U.S. Constitution and in his right to privacy."

“The Supreme Court has held that there is an extraordinarily high privacy interest in the contents of an electronic device,” the ACLU continues. “On the other side of the scale, CBP’s interest in searching electronic device is lower than its interest in searching luggage for contraband or dangerous items. No customs-based rationale justifies the search of sensitive private correspondence wholly unrelated to concerns about contraband.”

This seems like a Fourth Amendment issue of unreasonable search and seizure. But the rub is that the confiscation of this smartphone and the demand for a passcode occurred at an international terminal at SFO — which is legally considered a U.S. border, not the United States proper.

“Fourth Amendment protection is not as strong at the border as it is in your home or office,” the Electronic Freedom Foundation explains. “This means that law enforcement can inspect your computer or electronic equipment, even if they have no reason to suspect there is anything illegal on it. An international airport, even if many miles from the actual border, is considered the functional equivalent of a border.”

But California is among those states whose laws expressly say that customs agents “can only confiscate an electronic device and conduct a more thorough ‘forensic’ examination of it if they have reasonable suspicion you’ve engaged in criminal behavior,” according to the EFF.

Troublingly, these cell phone seizures at the border are on a sharp increase for both U.S. citizens and for immigrants. An NBC News analysis found that 2,756 cell phones were seized and examined at U.S. borders in January 2017, and 2,299 were in February 2017 — compared to an average of 1,586 in each month of 2016.

Related: Feds Tell Local Police They're Happy To Help Unlock iPhones