Barnaby’s Cafe in Houston staples their copy of the credit card receipt, the one I have to sign, to the check. At restaurants there is often confusion over which copy is which, and people inevitably write out a tip, calculate the total and begin to sign before they realize they’ve written on the wrong copy.
Barnaby’s simple solution is to staple the receipt to the large customer bill. When they do that, I instinctively know which I’m supposed to write on. I’ve never made a mistake there.