Right, so you're saying it up to me to notice and call the credit card company?
In that case, I need to go through my statement and remember that the $70 charge was supposed to be $60, or have the receipts and check it. That isn't something I have to do here, because it all happens at the same time.
Or are you saying that the penalty for the restaurant/server is high enough that this sort of thing just doesn't really happen much?