I've just tested and with Google hangouts, at the very least, switching off the camera in the hangouts UI results in the laptop green light being turned off. (

I've just tested and with Google hangouts, at the very least, switching off the camera in the hangouts UI results in the laptop green light being turned off. (With Facebook messenger, OTOH, turning off the camera in the UI does not cause the light to be turned off, just like OP described. I haven't tested the other sites/applications, now, but in the ancient times of the old (Qt?) Skype program, the laptop indicator would be turned off when the video stream was turned off.)