Earlier quoted context omitted.
The bump would go towards the keyboard, I'd think.
There's very little clearance in that direction, and the clearance which there is is necessary for the screen / lens not to touch the keyboard / case and get scratched. So if you have a bump on the inner side, you also need to have a notch in the topcase. And unless you move the webcam something weird (an edge or below the screen), you need to have that notch through or below right below trackpad, which is less than…
Would it be so weird? I mean: top corner/edge is less of a problem than bottom (nostril+big hands)
Assymertic? let's go nuts: two webcams, one on each side... suddenly, no notch, double the amount of light, stereoscopic vision. Combine that with some software processing and probably two very cheap sensors could produce decent results without bumping the price as a thin and tiny high quality sensor would.