If the blue lights are illegal, there sure a lot of people who are NOT being pulled over for having them.
I mentioned in another reply, about someone having green headlights. He was driving around town last summer with them. They looked like the headlighs on that old "Green Hornet" tv series. That same night, the cops did pull him over. I'm not sure if it was because of the lights, but I bet it was. That was the last time I saw those green lights too. So either he was made to change them, or else he was not from town.
Another oddball thing are these kids who have lights under their cars that make the road glow. (Usually purple). I never understood why anyone would spend money on something like that. They are not annoying though, but they sure make no sense. I doubt any of them survive winter, or maybe they remove them before the snow comes??? I always wondered if those were legal?