In a perfect world, with true freedom of speech, you should be able to put whatever stickers you want to put on your vehicle without fear that someone will vandalize it. Likewise, those people you saw should be allowed to wear whatever Obama loving apparel they wish to wear.
I could care less what they wear and wont bother them, but the same is usually not true in return. A palin bachmann sticker near me would get a key mark all along the fenders, blown out windows and tires, etc.
These savages are not worth it. my car to me is more important than their impulsive need to lash out and destroy property.