Boys, boys! Yep, the idea is at least one umpire should know who has the ball, then if the hidden ball trick is tried (or any other kind of dead ball "pickoff", for that matter) the "knowing" umpire can step up and say, "The ball's still dead". No real need to get excited making that call - just point it out matter-of-factly. If a team wants to make a fuss after that, it speaks volumes about THEIR knowledge of when a balk can be called. Oh, eye contact with your partner is a very valuable tool and cannot be stressed enough.
