Except that it isn't just skill, it is a lot of luck too, and why would I want more luck involved in who wins? If there were no luck involved in these break outs then I could understand the rule, but the fact is there is tons of sheer luck and chance involved. And if for some reason it really mattered if more than one ball went in on a shot then I could understand that too, but that doesn't really matter either. The rule is awful arbitrary and just serves to introduce more luck into the game and that is the rub. They don't penalize that same thing in straight pool for those reasons.