You put a bit of tape over the camera, but the mike you just have to turn off... which means it can be turned back on. And yet we keep doing this.Oh, you're quite right. I figure that at least desktop devices are stationary, and do not contain cameras or microphones (that I know of.) The hardware is also simpler, and easier for me to understand than the myriads of inaccessible small circuits in touchscreens.
