While what you say would make sense, we have a canon example that seems to disprove your theory. In one of the main missions involving tracking down Evelyn, V has to watch an XBD from the perspective of a kidnapped victim being tortured to death. The XBD is in 1st Person, clearly scrolled using the optics of the user, and the torturer's face is distorted. The effect persists even when you switch to 3rd Person. So, yes, the protection appears to distort optics as well.
The much more sensible theory, in my opinion, would be that you can simply switch the function off, like all other programs. Someone with a shielded face would draw attention if they walked across a busy mall, which misses the point, but they can just disable the function until they're doing something they don't want traced. In that situation, you don't want anyone remembering your face anyway, so no problem with having people talk to distorted blue pixels. Well, unless you're so terrified of offending your partners that you're willing to risk being connected to the crime and being tracked down later to avoid doing so.
Actually, speaking of blue pixels, I could have sworn that some of the stronger enemies in the game (certain Cyberninjas and other spec-ops) have their faces distorted as you fight them, just like those Scavs in the XBD. Can someone confirm this, or am I misremembering things? Because if I do remember this right, it further supports my position.