Urging people to stay in a fixed place without the chance to move out is a criminal offence, imho.
And plase dont tell me now that it may have cost 2000 pounds or something to get the people back through immigration..in Heathrow.
If I were a passenger from the US, with a ticket purchased in the US, I would sue them from here to Jerusalem, if they had forced me to remain on board or manhandled me when I gtry to disembark.
I am really serious here. I am sure, the passenger would win in a court in the US.