[justjim]

Originally Posted by noslices1

Since the waiter picked up the "unsigned slip", then possibly, the diners did sign one of the slips and took that one by mistake. The waiter should have just added 20% tip and turned it in unsigned. If there was a credit card used, I doubt if this was a case of "dine & dash"

You get your bill first then give the Server your credit card. At this point, when you first get the bill, is when a “dash” would happen. Despicable and sad but it happens.