Actually....no. Under federal law the airlines are required to compensate you up to $1300 for an overbooked flight leading to a delay of more than 2 hours to your destination. Contract of carriage says that United may deny boarding to an overbooked passenger but once he boarded the plane the passenger was under their duty of care and should not have been forcibly removed. United has no grounds to take passengers out of their seats on a bogus "tresspassing" charge due to overbooking not allowing enough room for United personnel and will rightfully be sued for this.