Before I read anything past the OP ...
No. For the umpires on here looking for advice: do NOT EVER do this. If you are watching a game, do NOT talk to the umpire. If you are umpiring a game, do NOT talk to the fence.
If a coach wants to take direction from the crowd, that's his/her prerogative (although things like dad sitting behind home plate and providing intel is illegal). As an umpire, do not do this. ALL COACHES NEED TO BE IN THE TEAM AREA (dugout). The bookkeeper who is sitting behind home plate is NOT team personnel if he is not in the team area. I don't care if the wrong batter is up IF the bookkeeper is screaming at you from behind home plate.
The guy asking umpires on this board about out of spec softballs doesn't see an answer anywhere here.