The 'allow getusermedia' policy is handled by the browser, not javascript. It's possible that some day there will be a browser bug for bypassing it, but you ca

The 'allow getusermedia' policy is handled by the browser, not javascript. 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.