I got given one once and tried to pass it on, shop noticed and refused to take it, so I passed it in another shop down the road. The next morning I was awoken by police with a warrant to search my house looking for more notes, I said I only had the one and I was just trying to get rid of it so not out of pocket, got a caution (was 1st offence) for obtaining goods by deception using a fraudulant instrument.