I suspect it's one she's sending to everyone on her Facebook friends list, because of the 'if you haven't already' stipulation. I have the following to say about it:
1. She doesn't offer Buttercup a copy of the book to read; it appears that reading the book before assessing it is not deemed necessary by Hyacinth. She just wants a five star review - not only from a total stranger, but from Buttercup's friends, too. What sort of nutcase is this??? At least offer a copy of your poxy book, luv! At least pretend you want them to read it!
2. Asking people to give you 5* reviews without having read your book (asking them to give you 5* even if you want them to read it first is bad enough!) is not 'networking', it's asking people to abuse the reviewing system and mislead the reading public. If you've had a request like this, please express this to Hyacinth!
3. Most bona fide agents care little for Amazon reviews, as they know how open to abuse the system can be - and people like Hyacinth are responsible for giving them this impression. Agents care about whether your manuscript is up to scratch, not how many pals you've got.
4. Hyacinth, I've looked at your book and you have several one star reviews. If you have to ask people to write fake ones in order to get the rating you want, perhaps it's time to revise your book.....