This is an important thing to tackle too. Amazon is notorious for allowing shady practices like Sell product A for lots of 5* reviews, then change the product listing to a completely different thing (which may or may not deserve 5) ...
Another aspect is review solicitation. eg: ios games often pop up with their own modal of "Rate us" and if you click 5 it redirects you to app store to make a review, if you click 4 or less it redirects you to a feedback form. They grease the path for positive reviewers.
Another aspect is review solicitation. eg: ios games often pop up with their own modal of "Rate us" and if you click 5 it redirects you to app store to make a review, if you click 4 or less it redirects you to a feedback form. They grease the path for positive reviewers.