I've heard a little about this too. I couldn't do this even if I wanted to. One: I don't have a heavy oil ball. Two: It takes me all of practice plus half of the first game to get loose and figure out my own line.
I agree that it seems like cheating. I want to win because I've executed better shots than my opponent, not because I've messed up his or her line. I have at times been tempted to play mind games with opponents who get very emotional, gut so far I've been able to resist.
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