I don't think they are related. I think what stops that from happening is open feedback across the company and hiring the right people. No one is really thinking, "man I would totally screw this person if not for the bad review they might give me!". Especially since the reviews only happen once a year.

If you do something negative to someone, that person will either directly address it with you or your manager at the time. The reviews are more to address longer term behavior.