Back when Costco accepted Discover and allowed cash-over on purchases, when I took cash over, I would be asked by the receipt-checker, "did you get your $30?".

Back when Costco accepted Discover and allowed cash-over on purchases, when I took cash over, I would be asked by the receipt-checker, "did you get your $30?". On two separate occasions, I had in fact forgotten. One of those, I was given the missing cash immediately without question. The other time, the manager was skeptical but agreed to close and count the drawer, and I received the $30 immediately after that process.