Adopted the whole underlight thing first. Used to see cars cruising around with them. A lot of places will outlaw them just as a way to harass the gangbangers, and claim it’s a distraction and safety hazard.
But heck, maybe they’ve got studies that show they really are a dangerous distraction. I never looked into it, because when your ride is a Saturn SL or Honda Accord, stuff like that will make you look stupid, not cool.