I seen a lady who opts out a few times, meetings were great. She told me that she didn't allow reviews because she didn't like anyone commenting on what happened, good comments too. To each their own, she wasn't comfortable with it so she kept them off.
But saying that I only went to see her on recommendation from others. Usually I will not go to a provider that opts out, too many horror stories. The above lady was a rare exception to the rule only because she was recommended. There are so many fantastic providers that allow reviews that you shouldn't feel the need to take a chance