Pretty sure you have to be under arrest for them to be allowed to conduct a search off your person, and have a warrant for them to search the phone.

So the issue is that he entered a code that wiped his data, but what is he entered a code that opened a dummy profile?

IF (extremely huge "if") I ever go to the US, it will be without a phone. I'll just bring a meshcore device for me and whoever accompanies me and a digital camera (thoroughly wiped before going there). I'll add some laptop or handheld (a wiped steam deck could be perfect) just in case I need internet access for something like my bank, but in absolutely no way I'm travelling there with my phone or any kind of personal device that has the slightest portion of my personal data for an asshole to try and find it.

When I recently reentered the country this year there literally was no security process other than scanning my face and my passport at an automated thing. After that, it was just walk on through. No talking with any agents, no search of my carry on bags (at least until going through TSA to fly domestically).

I think people’s checked baggage was heavily scrutinized and scanned, but not any carry on. It was honestly kind of crazy. Like what if I had come from a country with virtually no exit security, and then was not flying domestically after that? I feel it would have been quite easy to smuggle things into the country in that case. Meanwhile they occasionally freak out and force people to let them search their phone? It makes little sense to me