Hehe I accidentally do that at work- but only when I'm entering how much they're paying. (Like putting in 20002000 cash because I forgot I already typed $20 once) xD
"... as long as you don't want change, that is." xD haha no, but they always look at their receipt and say: "Sooooo, where's the rest of my change?" lol. Not even every store in the building would have enough money to give them all the change their receipt says they get back.