Yes, I've made this after reading the post. Thanks.

I haven't read that particular comment though. It is obvious that QR codes are a security concern. First, QR code readers are required to ask for permission to open URLs. They might as well not implement it or could have malicious codes for misrepresenting the URL in specific cases. Second, I wouldn't be surprised to see some bugs exploited in QR code scanning code by giving them strange codes to scan. These would not look like valid HR codes but would look like just another QR code.