I saw both plays and it was a good call IMHO on both counts. On the Barber play, the Steelers player was riding Barber out of bounds, then lets go, which causes Barber's momentum to make him fall. No push, no hit, just letting him go. As for the late hit on Big Ben, there were 2 linemen smothering him, the whistle had blown, then the safety comes in and knocks him down. It didn't look so bad on replay, but looked like a penalty in real-time. And QB's are WAY more protected than any other position.