I'd love for a third party to verify the claim! I'm just giving you an overview of the work that went into making this a thing, knowing full well you have absolutely no reason to trust me.

The LED being "hard-wired" is a tricky statement to make, and I actually wasn't aware Apple has publicly ever made a statement to that effect. What I can say is that relying on the dedicated LED or "sensor array active" signal some camera sensors provide, while technically hard-wired in the sense there is no firmware driving it, is not foolproof.