What reason(s) might there be for reviews to disappear? I have been keeping an eye on a particular provider as I try to decide whether or not to see her. My decision process entails looking at her reviews, of course, and 2 recent ones (both since the beginning of the year, and both gave rather high marks) have disappeared. Anyone know why that would happen?

1) She asked to be delisted or  
2) The reviews were found to be fake so removed.

I repeat with my faves.  I've had repeat reviews of a few removed.

TER's rules, and the mods didn't catch it initially, then they can remove the review even after it went up.    There are specific service  requirements for a provider to get more than 7 points for service.  If a review is non-conforming, the mods will automatically disallow the review.  They do not allow editing of the narrative to conform to the score they WANTED to give, as this leads to fakery and then the review is worthless to other members.  

I've had a few reviews of my own disappear and then noticed those specific reviewers can no longer be found.    
These were real reviews which had been there for some time, then poof!  Gone.  
The reviewer and all his reviews had disappeared.  

is that the provider or someone else had strong evidence that the reviews were fake and had them removed.