I went to a BurgerKing - they had yesterdays discount sign still up. As I was in line, the noticed, and took it down. I demanded they still give me that price.
I argued with the manager for 10 minutes. Finally he went to the back to call headoffice about their policy. Five minutes later, he apologized, offered me yesterday's price, and handed me the burger.
I ate it.
Yeah, that's living on the edge - lots of time back there, and nobody to see what he was doing.