[dpark]

What stops malware from doing this already? If your PC is compromised, what stops it, today, from popping up a message that says, "hey, open this url on your phone to [fix your registry|enter this contest|get free porn|pay our ransom|whatever]"?

No new attack vector was created by adding QR codes to BSODs. Most people aren't going to scan the QR code anyway, for the same reason they didn't search for the error codes: they done know what to do with the info. They will restart the machine and eventually call a friend/relative/tech support for help.