Two patients escape from a mental hospital…
…Needing money to get out of the area, they steal some clothes from a house and shotguns from a gun club, turn them into sawn offs, and go to rob a bank.
Walking into the bank, they wave the sawn offs around shouting, “This is a robbery! Empty your pockets!”
The teller takes one look at them and says, “You two must be the escaped mental patients.”
Shocked, but quickly recovering, one yells at the teller, “No we are not, and even if we were how could you tell?”
“You’ve sawed the wrong end off.”