I have nothing on my car, as I work at a college, and just don't want my car to become the object of campus police interest. The NRA pin adorns my lapel daily, however, in and out of the classroom. I also bring old copies of firearm magazines (with mailing label removed) into the faculty dining room and leave them on the magazine rack, just to antagonize the liberal-socialist pukes that I must associate with.
I'm retiring in about a year & moving to Texas; the decals go on as I leave town.