Bezos-owned Washington Post published a large story on Amazon fake reviews, but that's just the beginning. Years ago I bought an Anker Bluetooth Keyboard. I gave it three stars despite its rock-bottom $20 price, as I couldn't imagine using it beyond the lightest use cases as the feel was abysmal (keys were squishy and wobbly). It technically "worked" but even if I were given one for free, I'd still would have not like the product. Price and value are interconnected, but there's a floor where simply the value of an object ceases increase regardless of how low price as my affinity for the product will not increase.
What followed was Anker harassing me to change my review. I admired they wanted to "fix" the situation but the product worked as advertised so there wasn't anything to fix. Had they left at that, then this would have been the end of the story.
Anker e-mailed several times, although I deleted a few of the e-mails. I believe the count was roughly 5 emails, near daily. I grew tired of it and contacted Anker, and they inferred that they were willing to give me at least more Anker products (it wasn't entirely clear) beyond a second keyboard to reconsider my review. Anker crossed a narrow ethical line. They didn't offer me money, but they were willing to sweeten the pot for me to reconsider under the implication I'd consider changing my star rating. Long story short, I did not change my review nor did I take Anker up on offers. The keyboard was mediocre and short of re-engineering it, there was nothing more to say. Giving a second mediocre keyboard, wouldn't have equated to one good keyboard.
I'm willing to bet Anker didn't violate any of the terms of service for Amazon and the value of a real customer (me) changing my review, in exchange for some bonus swag (cables? I'm speculating) they, essentially buy a review without "buying" a review. This struck me as insidious behavior and a general mistrust of "Amazon" brands, products that seem to exist entirely in the Amazon ecosphere.
I realize I'm singling out Anker but it's also the company I've had first-hand experience with. Even in 2013, fake reviews were a problem but this alerted me to a new form of review inflation. I've been far more skeptical of the "Amazon" brands since, those companies that seem entirely exist in the Amazon eco-sphere, usually selling cheap electronics or knock-offs of more popular products with strikingly high reviews, like popular Symphonized, selling stylish headphones at cheap prices.
Does Symphonized pay reviewers or harass negative reviewers? I don't know and that's problematic.