I'd imagine a combination. Overzealous and probably demanding border guards, the traveller getting offended by that and not showing them the respect they think

I'd imagine a combination. Overzealous and probably demanding border guards, the traveller getting offended by that and not showing them the respect they think they deserve... Then they throw the book at you :( The problem is that normal US law doesn't apply at the border. They even held an American NASA employee with a security clearance and this was before Trump. It does look like it's getting worse now though. I'm definitely not going to the US anymore even if my work asks me to.