Dealing with fake/fraudulent reviews is hard enough, this is probably harder: manufacturers incentivizes real customers to write good reviews & remove bad reviews. I recently bought a few highly-rated gadgets from Amazon. One of them came with a leaflet saying they would send $50 gift card (the product costs $200) if I review and send them the screenshot. For another product, after I posted a 3-star review, which was not at all negative, I've been receiving a dozen or so emails from different addresses with varying subjects/contents but all asking me to remove that review in exchange for a gift card. I could only imagine how much harder they would go after the 1-star reviews...