7) Pickled Revenge
I worked at a steakhouse in the Midwest, and in our lobby during the holidays we had a display table with bottles of wine filled with red vinegar. One night a kid grabbed one and walked out with it. Our hostesses were all high school girls, so of course we told them to not take any sort of risk.
A few days later, a lady called to talk to our GM. She said her son got her a bottle of wine from our place and that it was bad and tasted like vinegar. Our manager just started laughing and said, “Your kid stole the display bottle from our store. It WAS vinegar, and did you not think it was odd that your underaged kid gave you alcohol for a gift?” He then hung up on her, and she never called back.