Any client an escort sees is a potential reviewer. Since many of us sometimes or always book without saying who we are, every client is a potential "trusted" reviewer. So an escort who doesn't consistently treat clients well isn't going to last very long in this business.
Do some "trusted reviewers" abuse that status to get discounts, stay longer, etc.? Maybe. That's certainly a risk. If you know anything about any such cases then you should report them to mods or staff.