While the violent part of the incident is the fault of security (why should a non-violent, non-threatening passenger have violence used against him???) the airline should never have been in this position. Stop overbooking flights. Pay to put your 'deadhead' crew on another airline. OR offer passengers an incentive above the one they are entitled to by law instead of trying to get them to accept less than that before giving up. It's just terrible business practice because they know they can usually get away with it and can save themselves a few $.