Apparently yes in some cases, iSeeYou: Disabling the MacBook Webcam Indicator LED [1]

[1] https://jscholarship.library.jhu.edu/bitstream/handle/1774.2...

I think when you're a person as important as Zuckerberg - it'd not be unreasonable to think you're under surveillance by other governments and so you probably can't easily guarantee that your hardware hasn't been tampered with.

The light is controller via software, it would be wiser if the light took power from the camera (e.g. if camera was powered the light would be on), but currently it doesn't do that.