@hannah Someone also kept putting up a little placard next to a fire extinguisher in a museum stairwell, causing people to stop and study it, and the museum kept taking it down.
Then the museum realized it was selling postcards of a photo of the fire extinguisher with the placard in their gift shop, smuggled in and printed with an existing postcard UPC.
The artist sued for their $10 in royalties. Everyone was very amused and/or pissed off.
edit: its Dove Bradshaw, see reply/thread