No, but he should have stayed until the game was officially over. He always seems to do things like this (like with Mangini and the handshake), and it's never his fault, he didn't know, it was an accident...save it.
As a coach, it was responsibility to stay for the entire game. If there was :01 second left and HIS team had the ball...would he have left? NO.
I think it was very UNproffesional in a PROfessional sport, and shows what a pathetic jerk he really is.
Remember Moss leaving the field in Minnesota? He was a quitter, a bitch, etc...and the same applies to Bill. In fact, more so, because he's the LEADER of this team, and he left some of his players on the field, not knowing what to do. Watch the last play, as the players are coming onto the field...they're looking around like they're confused. THAT is his fault, and if I was a player, I would have let him know how I felt about that.
That's my take on it...