This is the most correct and obvious/very low cost way to do it that you almost start to think Amazon is in on the conspiracy with these fake reviewers because they have something to gain that we are not seeing.
That's the thing I don't get. Amazon wants to have reliable reviews, right? If people have to go elsewhere for reliable reviews those better-run sites will start affiliate programs with other sellers. That's a real risk for Amazon. I don't really care where I buy dog food or computer accessories or whatever. I live and breath AWS so they've got me there, but buying goods from them or target.com or wherever else is ultimately all the same.