New legal news on a favorite blog post topic -- the legality (or not) of flashing one's headlights to warn oncoming drivers of a speed trap ahead. A federal district judge in Missouri came down on the side of the flasher in this opinion issued Monday finding that the policy and custom of police officers pulling over, detaining, citing, prosecuting and fining drivers perceived as having communicated to oncoming traffic by flashing their headlamps has a chilling effect on the drivers' First Amendment rights. Eugene Volokh is not so sure that's right:
When I’ve blogged about this in the past, some people have argued that flashing headlights should be protected because it’s encouraging legal behavior (slowing down) rather than illegal behavior, but I don’t think that can dispose of the issue: Many lookouts do the same, e.g., when a lookout warns would-be robbers to abandon their plans because a police car is driving by. [UPDATE: Remainder of paragraph added.] Moreover, a headlight flasher’s warning to speeders seems likely to (and probably intended to) slow them down only until they get past the police car — they’d just be postponing their illegal act by a few seconds. That’s why the “he’s only trying to get people to be law-abiding” argument strikes me as weak; what he’s actually doing (and trying to do) is decrease the cost to drivers of breaking the law.
Favorite comment to Volokh's post? "So, when the police put up an electronic sign on New Year's Eve warning people that there will be extra DWI patrols out, are they facilitating crime?"