People who put bumper stickers on their cars are seeking identity and validation.
The more stickers the more mentally unstable the driver, IMO.
I don’t put any stickers on my car. I have sort of a herd animal mentality about it. I’m out there on the savannah, travelling as necessary, and I don’t want to give anyone any reason to single me out about anything. I don’t want the cops to have any special reason to look at me. I don’t want thieves or psychos or anyone to draw any conclusions from my car. I want to be incognito. I want safe passage to and from my destination. I want to travel unmolested. Hence, a clean, unmarked vehicle.