It only takes one nutjob, Kelly. And unfortunately there are plenty of nutjobs on both sides...
Here's one recent example of what happened to a woman with a McCain bumper sticker on her car:
Please note: I am NOT saying that all Obama supporters would mug you, let alone carve his initial into your face with a knife! I fully realize that this guy is a CRIMINAL, should be a felon if he isn't already and therefore shouldn't get a say in the election, and that Obama's campaign has decried his actions. All I'm saying is that there are nutjobs that just might stone someone's car for having a McCain sticker on it. Just like there are nutjobs who just might stone someone's car for having an Obama sticker too.