@gentlegardener @Natasha_Jay It used to be that if your paperwork wasn't 100% in order then US Immigration officials would simply stamp your passport "entry refused" and put you on the first plane back to your home country.

Or more likely (especially if you were polite & white) if the mistake was a very small one they'd let you in anyway.

And it works both ways, I know a number of Americans who have been refused entry to Britain for various reasons to do with invalid visas or incomplete paperwork.

But this incarceration thing that seems to be happening now is a whole new ballgame, at least for white citizens of western European countries.