One of the funniest magic things I've ever seen was Tagged gone wrong.
A magician I know "Tagged" someone with a card but didn't get a chance to finish the trick. About 15 minutes later the girl who was "Tagged" noticed.
"Who put this Seven of Spades stamp on me?"
The magician who did it pleaded ignorance. It was hilarious.
That's why I don't do these kind of tricks.
FAIL.