I've been asked numerous times if I'm a member on here and if I write reviews, and my answer is always "never heard of it"
I've never been asked to write a UKP review, but interestingly a few times I've been asked NOT to write a UKP review (even though I say I'm not a member). The thing is, they were both very good punts, so it's not like they were asking me to hide a neg, as they would have been strong positives for both. I really didn't understand why they wouldn't want a good review on here, but they didn't.....
We all could care less about the wishes of a genuinely bad SP, whether willful or unsuited.
So re: "good" SPs:
A good review beats the bushes for all manner of punter to make a b-line for an SP, that includes a fuck-ton of complete cunts who are neither honourable, well-mannered or respectful of an SPs limits. So it wouldn't surprise me that some SPs who are happy with the amount of business they have would say they don't want a review.
You could argue that increased popularity would allow them to up their rates and capitalise but that wouldn't guarantee avoiding all the shitty punters and would also run greater risk of negative reviews whether or not justified. And of course with any increased reputation comes the possible coercion by arseholes who threaten negatives unless they get special treatment.
Any good SP should expect to be reviewed but there's no harm in asking for no review if they believe it will adversely affect their working conditions. It would be interesting to learn if this is indeed the reason given.
I don't see a problem with SPs asking for reviews though probably better after the event so that the punter isn't placed in a position to exploit the promise. It would be extremely short-sighted of an SP to believe she can over-perform for that one positive and then let things slip subsequently as a string of negs should kill off any sustained uptick in business. This is the one best reason for all of us to publish our negatives as close to the event as possible (no excuse not to, use a punting number and email if you're worried about blowback). The balance to this is that Positives and Neutrals should also be lodged as close to the event as possible so that bad behaviour here can be patterned out and to best protect out experiences from being fucked by exploitative shits who drive good new SPs away.