I knew some people who would do this on Saturday nights. The rules were you couldn't steal letters, only rearrange them (and they'd leave any extras under the sign).

A cop caught them getting into a car and started asking a lot of questions. They were in a vet clinic parking lot and he let them go. The whole time they were like "please don't turn around .. please don't turn around" .. the sigh said something about licking pussy.