I'm not going to add to the United is stupid commentary. I concur with all of it. What could they have done to correct the situation at the start? 1) The attendants are supposed to go down the aisles to check for unoccupied seats before calling in standbys. If they had done that, they would have noticed that the son was sitting in his seat and corrected the seating chart. 2) Once they (should have) realized that there had been a mistake in seating the standby person, they should have asked the standby to go back to the gate, or reassign him a seat, instead of forcing the kid out of his. 3) The standby person should have realized the situation and left the seat rather than be selfish and take the seat away from the kid. He's not mentioned by name, but I think he owns some responsibility for the situation. Think about it. Would you take away the kid's seat? Selfish jerk.