As far as the Apple iSight goes, I personally don't really think Apple has a way to remotely disable the green light while the camera is on, but I have to admit I'd like to see rock solid evidence for that via wiring schematics as well. I've never seen any evidence, just hearsay. And, I'm sure as hell not going to take Apple's word on it.
Maybe iFixit would take the challenge to prove it once and for all? I dunno.