I recently ordered a small device from Amazon, it was poor, so I gave it a 1 star rating with a short, negative review.

About a week later, I received an e-mail from the seller (via Amazon's payments communication system) asking for me to delete my review in return for being refunded the total amount, and stating that I could keep the device.

Whilst I didn't take up their offer, I assume many others did which shows how Amazon is 'not flooded with one-star reviews'.