If you enjoy stirring the pot, go to one of the main RV sites and ask this question. If you think it get ridiculous here, you ain't seen nothin' yet LOL.
Laws do vary from state to state but what those that do it have stated is that unless you are already doing something that gets you singled out, you'll most likely be left alone. There are some exceptions like CA and maybe MD and others where they will pull you over if it is illegal.