The ticket is a contract, and it should be enforced under contract law. My experience (having been bumped involuntarily from business travel once and voluntarily from recreational travel many times) is that the passenger doesn’t get much for an involuntary bump. He is entitled to a refund of his money, or other specified compensation of typically a few hundred dollars, and anything beyond that is based on good will. I doubt there is much good will for the drama queen in this instance.
Note: When I was involuntarily bumped, it cost me a fairly large contract, although that contract was reinstated a month later.
United as an airline stinks. I wish Continental had never agreed to the merger. They pull stunts like this all the time. Once a passenger is seated, they need to move their crew using a different flight, or offer so much money for someone to give up their seat, that the person volunteers. I hope the damage award is in the millions. It should come out of the bonuses of the POS management team.