Sure, but I am asking if this can be modded to gain unauth access to the webcam.
It's possible that some day there will be a browser bug for bypassing it, but you can't just write javascript code that says "don't ask for permission".
Nowadays the majority of webcams also hard-wire their 'on' light, so the user would at least get an indication that the webcam is suddenly recording.
I don't know if how you'd sent it somewhere with the same origin policy in place.
nope, the "use webcam" permission is per "getUserMedia" call, so 2 getUserMedia calls = 2 allowbar popups.