By now you probably know about the incident and have seen the disturbing video. United boarded its flight to Louisville, Ky., and then couldn't bribe enough passengers to get off the plane to make room for airline personnel who arrived at the gate and had to make the trip. The crew selected four passengers at random who would be compelled to disembark, and when one of them refused to leave his seat, the airline summoned Chicago Department of Aviation security officers who wrestled and dragged the man, screaming and bleeding, out of the cabin.