What possible good would that do? You can't make them un-xenon. If I flash my lights or not, you'll still just keep toodling along blinding everybody in the oncoming lane.
If I see ultra-bright lights, I assume the other driver has the high beams on and flash them. If you can tell that they have misconfigured low beams, you wouldn't do that, but I'm going by my experience and assume that at least a few drivers would act the same way.
