I think technically yes. There is some HTA law that can be used against it. But it's one of those things that would be hard to prove that that was your intentions.Can you be held accountable if another cop sees you flashing the beams to warn other motorists?
Reason I ask is down the street where I live, cops team up: one is placed down the hill while the other all the way up as they snag speeders.
You could have just accidentally flashed your high beams while trying to activate your turn signal.