As an Australian who wrote about the demonstrations while on campus, I gave my phone a superficial clean before flying to the U.S. I underestimated what I was up against.
From the ACLU, it sounds like having an attorney's number and asking for a supervisor might have been helpful steps. Still seems like obvious free speech suppression by CBP though.
Refusal by non-citizen visa holders and visitors to answer questions may result in denial of entry.
If the officers’ questions become intrusive or improper, you should complain and ask to speak to a supervisor. (This goes for citizens, lawful permanent residents, or non-citizen visa holders and visitors.) Although CBP takes the position that you are not entitled to an attorney during primary and secondary inspection, we encourage you to have the telephone number of an attorney or legal services organization with you and ask to contact them if you feel your rights are being violated or if you have been detained for an unusually long period.
I opted against taking a burner phone—a move that some legal experts had advised, in the press—believing it would provoke suspicion, and simply decided to give my phone and social media a superficial clean.
But C.B.P. had prepared for me well before my arrival. They did not need to identify me at LAX as someone worthy of investigation: they had evidently decided that weeks before. [...] In either case, a U.S. government officer must have read my work and decided that I was not fit to enter the country. Because Officer Martinez had apparently read all of my material so long ago, he didn’t even know that I had taken all this material down. What this means is that, by the time a foreigner cleans his social media in preparation for a trip to the U.S., as much of our news media has been urging us to do, it may already be too late.
This had nothing to do with recovering any data from the phone. The information was already known to them.
They'll likely be suspicious if you have a burner phone. Fascism works in reverse, they figure out what they want first then come up with an excuse second.
You are using the same faulty logic the article's author confesses he did.
Though I did not know it then, I was participating in an interview that I was never going to pass.
If you got pulled, assume that they are already suspicious and are now just looking for more rope to hang you with. The question is, how much rope do you have on your person?
Almost everything is recoverable unless you do a deep scrub of the onboard storage with special tools, and even then I wouldn't guarantee it. You cannot recover what never existed.