One thing to note about the US is that card processing fees are more than double what they are in the UK/EU. It allows CC companies to eat the costs of fraud more without passing it onto the consumer/business.
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?
Same with stealing number. Yes it's kind of strange that most of the time the server just takes your card and disappears for a while, but I've never heard of a number being stolen from anybody I know. Of course, it does happen, but it's very rare.