I once saw a QR code advertised in a Buenos Aries subway station that was just a QR code and nothing else. No graphics, logo, or ad copy around it. So having some time, I scanned it. It was just text, not a URL. (I don't remember what the text said. But it was basically just "buy slurm!"

Seemed pointless to me. This is how the public interacts with QR codes - they can't do anything that can't be done by pasting TEXT where the QR code would be.