Can't wrap my head around that one, wouldn't exactly be doing the wg any favours. I'm sure many reviews aren't posted because a punter wants to get his fill of her or she might be a regular.
Sort of reverse White Knighting (or EAS).
There's some here, or have been, that have like to keep certain women to themselves. Tactically, if they were to put a bad review up, the average person here wouldn't go near her, thus meaning he can see her more easily and prices won't increase due to popularity.
I'm sure some do think along those lines, although hopefully a very small minority.
Same sort of thing as telling prospective buyers for next door's house, dodgy stories that put them off buying. People do do that sort of thing.
At the end of the day here, if I'm looking for someone, a negative review will generally put me off even considering her. I may read why she was that bad, but I won't try to book her (unless it turns out to be 1 out of say 20 bad reviews in which case it becomes a judgement call).