What happened was a civil and criminal assault and battery, though there is 0 chance that the officers will be prosecuted. The customer had committed no crime, and at least at the beginning, threatened no one (the "failure comply with instructions" issue can be sorted out later, but did not support the physical removal of the customer). Local law enforcement should have declined to be involved, as no crime was committed, and told UA that it was their problem to sort out. UA was in a pickle when the customer refused to leave, but it was a pickle of their own making. In the end, they could have further upped the offer, or chartered a jet to take their crew to the destination, if that was what they really needed. Appalling decisonmaking, an example of why some people should not be put in a position of authority, and a great example of why law enforcement should decline to be involved in an airlines screw-ups, when there is no threat to anyone. It's hard to tell from the videos, but the person who actually removed the customer may not have been law enforcement at all, and if he was private security he definitely committed a crime.