(Newser) – Note to Tennessee drivers: You may want to scrape any R-rated bumper stickers from your car before driving to the fireworks ... or anywhere else in the state. As of last Friday, motorists whose vehicles bear obscene or offensive stickers or markings will automatically be fined $50. And keep it clean inside, too: WKRN reports, somewhat bizarrely, that the fine also applies to movies, like adult films, that others can spot playing inside your car.

But some drivers are concerned the law messes with freedom of speech. "What is obscene to one person may not be to another," says one. "They are constantly arguing about what is obscene, what that definition is." But a Democratic state representative counters, "When you get into crossing the line so to speak you do not have a right to impose your speech on other people." Offended Tennesseans can turn in license plate numbers of nasty-sticker-clad cars to the police. (Read more bumper sticker stories.)

