So you hate those stupid internet advisories, but had to share with us?
Could it work? Sure. Lots of things could work, even a bunch that aren't done or about which there is no reality
http://www.snopes.com/crime/warnings/carjack.asp
http://www.hoax-slayer.com/issue57.html
http://urbanlegends.about.com/od/crime/a/carjacking.htm
Maybe gang members drive around with their headlights off in the evening and kill anyone who flashes them. It could work, but...
http://www.snopes.com/crime/gangs/lightsout.asp