The best way to prevent all of this from happening is to just get down and shoot the 8-ball. If the quarters bother you then you have a concentration issue. Focus on the task at hand and you will be ok.
The part that bothers me is the folks have to behave like this to try and win a game. I've never missed a shot yet on the "quarters" move, nor lost a match with it. It just irks me that folks stoop to this to try and win. I just don't like the fact that they do it, and are allowed to get away with it. Thus, why I'm going to take the "concession" win next time they do it... game over the second they take the quarters out. Problem solved. Bet after that they never do it again.