Originally Posted by Rdenney

Such as a boarding pass with that seat assigned to that person? That seems pretty convincing to me, at least convincing enough for the officers to realize that they have no standing in the confrontation.

Cops are not law professors, but they are trained to subdue in too many cases, rather than to defuse. In the video linked upthread of the uniformed officers handling the out-of-control woman, they made no attempt to subdue until she was off the plane. In this case, the LEO's were in jeans and ball caps, and tried to do their subduing of the passenger while in his seat. They lacked the patience of those uniformed officers, and the result was injury. But in that case, the woman had violated the terms of the CofC, and the airline had the right to ask her to leave for safety reasons, and the officers had standing to demand it. Dao did not violate the terms of the CofC, and, as United has repeatedly acknowledged, was in his seat legally, having demonstrated no behavior that would give United the right to remove him by force.

This discussion of property rights has been repeated over and over again in this thread, with extensive discussion. I know it's a pain to go back and review it, but I'm not suggesting that one does anything I didn't do.