Originally Posted by
east_west
The other three accepted the terms that were offered to them. There is no reason that UA and a passenger (or 1000s previously) can't agree to the IDB terms to exit the airplane. Most passengers will clearly just cave in this situation. The Doctor, quite obviously, didn't. I really recommend you read the linked article, it is a very nice legal analysis of the situation w.r.t. to definition of IDB.
As the Godfather might put it, we're making you an offer you can't refuse ... get off the airplane and take whatever we have to give you by law, or we call the cops.