>One of the reasons for including the tip is that when you tip in cash, only the waiter/waitress gets it. The other way, it is often pooled so that the people in the back - cooks, bottle washers, table cleaners, etc also get a piece of the action. Many of them are working just as hard as the waiter to give you good service.

I'm not sure how prevalent that it is. The servers are dependent upon the good will of the back-room staff. One who consistently stiffs them will suddenly find his orders appearing late, food cooked not quite to order, etc.

I've always paid in cash because my impression is that the credit card companies charge vendors a percentage of each transaction as a processing fee. I could be wrong about this, but I pay cash just in case.