Beeped at a cop car in front of me to see if it was illegal. It is.
Adam Rifkin stashed this in Crime!
So is flashing your lights to get the car in front of you to speed up or get out of the way. If you do this at night, make sure it's not a police in car in front of you. And, when they pull you over for flashing your lights, don't tell them you were just trying to get their attention, unless you have a better story than "There is what appears to be a drunk driver on the road way back there. I thought you'd want to know about it."
Ha! It's funny because it's true...