I'd suspect rather than interactive feedback, it might have been trying to let him log in with a QR code. "A popup opened and wanted me to submit my information" sounds like a login/registration form.

What are you talking about? Why are you using imprecise language like "popped the camera open?"

You've run into a site you view on chrome/firefox/safari accessing your camera without granting access a few times now?

Can you give us an example of a site that does this so we can reproduce? Or could you retract your statement and clarify that you did grant camera permissions for that site previously?

Otherwise, you're saying very casually there's a huge bug and security issue that no one else has detected but you personally have seem multiple times.

I've run into people on the internet misremembering things or not understanding how the browser works more times than I've run into browsers allowing access to system devices like the camera without a permission prompt.