I don't think that's very robust. The entire image could easily be fake, as the face is fake, and people already have fake backgrounds. If the entire image is

I don't think that's very robust. The entire image could easily be fake, as the face is fake, and people already have fake backgrounds. If the entire image is fake, there's no reason for the actual camera's view to match the fake image, so a wider angle camera would keep you in view as you move, and the system could generate a tighter fake view.