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

Years ago, I "didn't" get stopped.

I'm going up this hill in my beat up FJ-40. Back in those days I had "landing lights" (4537s) I also tried to be careful with blinding people, and resolved to "give them 3 chances"

Again of me, going up this hill are THREE other cars. A car is approaching, brights on. The first car flashed his lights. The second car flashed his lights. The THIRD car flashed his lights. "Well," I said, "that was three chances." So I flashed the landing lights.

The approaching car STILL did not dim, and as he went by me, this was a STATE COP.