We had a yard sale this afternoon, and a fellow came up and bought a pile of DSL equipment. He asked us if we could break a $100. We said 'sure' and I went inside (we keep most of the money inside) to make change.
I came back out with 5 $20s and we did the transaction, him taking the modems and his change.
My wife Scarlet, said just after he left, "Check that bill." She just had a feeling.
Sure enough, the watermark on the bill was the one for a $5 (it wasn't Ben Franklin, like the other $100 bills we got today). I ran after him and confronted him about it and we reversed the whole transaction (yes, the $20s he gave back were legit).