This. It's why it's so important for laptops to permit a physical slider to block the integrated camera. It is a low-cost, low tech way to verify that the camera is not picking up usable images.
The real problem is that we don't have something analogous for microphones. The best we could do is some kind of humming device that you could turn on near the sensor that would drown out any noises it might otherwise pick up (and also be unobtrusive).
The real problem is that we don't have something analogous for microphones. The best we could do is some kind of humming device that you could turn on near the sensor that would drown out any noises it might otherwise pick up (and also be unobtrusive).