The engineers and techies involved have so far shown themselves to have poor intuition for understanding how the law is going to react. I think it behooves anyone still listening to their advice to also check in with someone who has a good intuition for how the law will react to this new idea.
The officer will say something like "That's your choice, but I will need to seize the device to conduct an analysis. It will be returned once the analysis is complete".
Then you shrug, and they will let you enter the US. The cops will try to get into the phone, fail, and return it to you.
Just bring a phone you don't mind losing for a few months.
They were never going to let him just walk in. Eventually, they'd have to, possibly after lawyers and news would get involved, but it's not like saying "no" was going to end the ordeal right away.
Of course they shouldn't do that to US citizens, but they also shouldn't be targetting protestors they have a personal gripe with.
It’s a completely different situation.
It happens, it's not my fault though.