Allegedly, some Harmonix employees are leaving 5-star reviews on Amazon for Rock Band 4. Reddit, as they tend to be, were on the case.
Harmonix employees seem to have taken to Amazon to post their own favorable reviews of the game. At first I thought it was a rogue employee or two but then I dug around for about a half hour and found 7 of them and so it appears to be more of an initiative. I'm sure there's more than that.

Some of the names in the reviews do match the names of employees that are at Harmonix. These names include Chris Foster, Nick Murdy, and Matthew Nordhaus.

Usually, the unethical practice of astroturfing is a little less obvious than what we're seeing here. Some people, people on the Internet, are a bit upset about this since, you know, companies (employees) really shouldn't be reviewing their own products. This is all assuming that these reviews are actually from the Harmonix employees in question.