I have the desire to avoid people hanging out immediately behind me, too, in the sense that it can keep me from losing myself in my work. In my case (and maybe in GP's case), the issue is not that they can see what I'm doing, but that it increases the expectation that I'm about to be interrupted, which destroys my ability to get into flow. A camera behind me connected to the intranet site wouldn't bother me in the same way.