Wait staff goes elsewhere to process your card, takes photo of it, runs you card and returns it to the table. Couple days later there is an alert or a charge for sneakers or something else. I've had it happen on a CC that isn't used often so I know when and where it happened not that anything would be done by complaining. Debit or credit it doesn't matter, its still a PITA when it happens.
I like now many restaurants have portable POS terminals and you can tap it at the table, card never leaves your hand.