"Apple laptop camera can't be active without the green light lit" -- Real, or a myth?

They say it's hard wired such that if power runs through the camera, it forces the green LED to light up at the same time.

Or to put it another way, it means if the green light is not lit up, it's a guarantee you aren't being watched by the camera.

Does anybody know, definitively, if this is true or not?

I know Apple does say this, but has anyone ever done a solid investigation (like for example physically tested …

apple camera can green guarantee hard laptop led power privacy real wired