0 expectation of privacy at an international border. This has been the law since King Narmer and should surprise no one.
In Criminal Procedure, many law professors skip this section of the book (a bunch of drug cases) and summarize the caselaw with “you have no rights at the border.”
2/3rds of the US is at such a border, and thus any CBP officer can perform a warrantless search of anyone without even the suggestion of any kind of probable cause. I'm honestly surprised we haven't seen police report anyone suspicious to the CBP in the knowledge that that gives them a direct bypass for any illegal search they want.
Doesn’t make it right.
In other words, would a judge accept evidence seized at the border in a case not about border law?