My mistake on the "flash to pass" I thought that triggered your regular old headlights when they weren't already on to begin with and that they flashed your high beams when your regular headlights are already activated. My bad and thank you for the correction.
People flash traffic because they don't want you to be able to stop the nitwit blasting down the highway - the nitwit with a 5 page KQ, who has a revoked license, who has a kilo of coke in the boot, who has outstanding warrants for diddling cub scouts out behind the parish hall. I don't believe this is going through the mind of the average person flashing their lights at oncoming traffic. I believe what is going through the average flashers mind is...(sarcasm on)Hey buddy there is a jerk cop up ahead trying to meet there monthly quota on tickets and is going to nail you for going 12 over the limit. I know you are only speeding because you have to go pick up your daughter from softball practice cause your wife is busy cooking dinner and even if she wasn't busy cooking dinner her car broke down last night and is going to cost you 500 dollars to fix. Hope you don't get hit with a 95 dollar ticket to add to your bad luck. Good day sir. (sarcasm off)
Really though what I am really trying to say is I wouldn't sweat the flasher over the speeder. I am just not a fan of strict traffic enforcement. I see where you are coming from though, but most everyone speeds...cops included, and cops almost never get tickets from another cop.