I am intrigued. That small square bumper sticker is a QR code. The camera on my phone isn’t powerful enough to read it (nor are most people’s, I suspect) and one can’t casually read it in traffic, so what could it usefully say?
“I brake for QR codes!”
“I’m in the grocery store; text me if I’ve left my lights on.”
“Only close neighbors and persistent stalkers need visit my website.”
At least I wasn’t driving home behind the salt truck again.