Flashing your lights to warn of speed trap is LEGAL FREE SPEECH!

"If you're at the gas station on the corner and someone says 'Hey be careful over there, there's a speed trap,' that's protected speech. You can't be ticketed for that. This is no different," Tony Rothert, an attorney for the American Civil Liberties Union, told Fox 2.

A federal judge has ruled that you can't be ticketed for that. Read more:
http://autos.aol.com/article/warning-drivers-of-speed-traps-with-flashing-headlights-is-free/