What counts as a fair book review?

Independent authors who publish their books on their own to Amazon owe much of their success or lack thereof to the star ratings given on their work. Higher average star ratings make their work appear in featured areas of the site and appear higher in searches. While a single star rating on a young book with otherwise high ratings can effectively destroy the sales pipeline. Even if a user writes, "I loved this book! It's perfect!," if they give it one star it will hurt sales. Similarly, if a user writes that they hate a book but they still give it five stars it will give the book more of a fighting chance in the market. There are a lot of users on Amazon who will target independent authors with one-star reviews simply to carry out a personal vendetta. The fickleness of star reviews and how great the impact is on sales has led many authors to see the star reviews as less an accurate reflection of the quality of their work than merely a marketing tool. (More well-monied authors and publishers sometimes even buy high star ratings.) So is it wrong to game Amazon's star rating system? Is it wrong for an author to ask their friends to give their books five stars even if they hate it allowing those same friends to write that they hate the book in their written review? Is it wrong for a reader to give a higher star rating to a book because they want the author to succeed but given an honest written review?