This habit some people have of stopping a cue ball after a miscue on the break shot is one of the things that drives me bonkers. In the APA league I play in, it is not a foul UNTIL the rack is struck. I see a lot of players stop a miscued cue ball on their break shots, I guess so it won't "disturb" the rack and time won't be wasted waiting for the balls to be re-racked. Here is the problem with that rule, IMO: Let's say that you are playing in APA Masters League where the 9 or 8-ball on the snap counts as a win. Let's say the match is hill-hill and your opponent is breaking (or you could be in a regular APA 9-ball match where the two players each need 2 points or less). A 9-on-the-snap here means a win for the breaker. He breaks, miscues, and the cueball is heading for the rack. He stops the cueball with his cuestick and repositions it and breaks and makes the 9 for the win. Now, on his first break attempt, what if he would have let the cueball continue on its path and it would have struck the rack, caromed off a ball and SCRATCHED??? Then, not only would the other person not have gotten the loss, but they would then have had the chance for the win themselves. IMO, this very reason alone is why stopping a moving cue ball should ALWAYS be a foul under ANY circumstance!!! No exceptions.
Maniac