It is helpful if the referee knows and is willing to enforce the rules. At the SBX warm-up event on Wednesday night a friend of mine was playing and his opponent shot the 8-ball. The cue ball was rolling toward the side pocket and it was evident it was going to just have enough speed to scratch. Just as the CB gets there the opponent places his stick across the mouth of the pocket and stops the CB. My friend calls a foul and the shooter says it was not a foul since he didn't physically touch the CB with his hand and any part of his body. They get the referee who asks the guy if he in fact stopped the CB with his stick. The man says yes, but emphasized he didn't touch it with his body. There was even a chalk mark on the pocket liner where his tip contacted it. The referee says that because he didn't actually see it, the call went to the shooter who proceeded to win the game. Later this guy scratched and subsequently lost the match to my friend.