zlacker

Yeah, the physical barrier is key. It's not that hard, and provides absolute certainty. As indicated by this thread, software experts (rightly) don't trust software by itself enough. It's by the same rationale software people are proponents of electronic voting machines printing physical, verifiable paper copies of votes.

My Latitude 7440 has a physical slider switch that covers the camera, in addition to turning it off in a software-detectable way (it shows "no signal" and not just a black screen once the slider is about 50% covering the lens). My only criticism of this is that it's subtle and at a glance hard to tell the difference between open and closed, but I guess you just get used to the slider being to the right.

I was just testing and the white LED comes on when I open something that wants to use the camera, even when the cover is closed. This seems like a useful way to detect something (eg malware) trying to use the camera, and is a good reason to not bluntly cut power to the entire camera module.