Idiots. I’ve seen the technique. Walk up to a self-checkout registers. Scan and bag all of the items. Attempt to pay, but clearly don’t provide a suitable payment. Kind of look around. Cancel the transaction. Pick up the bag(s), pull out a receipt from your pocket, casually walk around like you are looking for something, and then head out the door. Saw this happen clearly three times back in California. Two black males and one black female.
When I was a night-stocker at WalMart (10 years ago), we were told to pick up any receipts we saw lying on the floor. People would pick them up, select that item, and bring it back to Customer Service the next day for a refund.