I'm watching the film room broadcast of the game on ESPN2. Muschamp just said that DBs are taught to defend with their back to the ball is "eyes-hands-one one thousand- GO" meaning watch the receivers eyes looking for the ball, then wait for his hands to start going up, then count one one thousand, then swipe at the arms. Jim McElwain said it is an every day drill. I don't know if it is at ND but you can be sure it is at schools with really good DBs.
Also, I highly recommend the ESPN2 broadcast if you're into strategy/technique. It's very cool.