Originally posted by Falix
I find it extremely weird that this was allowed to happen without anyone at the time noticing.
Probably no one noticed because the mistake happened at the beginning of the fourth quarter when time wasn't yet a concern for either team.

Its also worth remembering that if the Patriots hadn't had time to kick the field goal, the score would have still been tied at 20. The Steelers would have needed to find a way to beat the Patriots in overtime to win the game.

Still, its a pretty embarassing mistake for the NFL.