A few weeks ago I saw the first QR code I've personally witnessed that I'm pretty sure is completely unscannable. The company logo stretched well out of the center block. It was on the back of a semi in the Chicago area. I didn't get the greatest shot of it on my phone (as a passenger), because it was driving away as I tried, so it wasn't quite proof it couldn't scan, but I'm pretty sure it ate more than 100% of the error correction margin.

Based on the trends, I expect it is only the first of several I will see.