This sort of gaming is rampant on Amazon. My own experience:

A friend of my wife introduced her to a woman who was a representative of a well known brand for home goods/kitchen gadgets. If you bought an item off Amazon of their brand, the woman would Venmo you for the value of the item provided you left a review. It went unsaid but understood anything less than five stars would mean the relationship was over. They also had a few other rules about your Amazon account to "qualify" (had to be personal, you had to review a certain number of other products, etc) to try to bypass any flags getting raised.