As long as there is a list of which SPs have requested to delete their reviews, I am OK with that. It is reasonable for an SP to ask to get her reviews deleted as long as the MERB community knows who requested this. The result will be that MERB community will know who is not being reviewed and people can make their own opinions about her.
The only possible loss is that you will have is one possible below average experience with some SP not being reviewed, but that will save you from having another such experience. Besides you can always PM your friends.