Just recently Amazon allowed me to buy a kindle book for my specific kindle device, which turned out to not be supported. But they still allowed me to purchase and deliver it to this kindle. Only once I went to the device to sync it did I learn that it was incompatible. I was not allowed a refund.

The reasonable behaviour would of course be to give a pop-up like "hey, you're trying to buy a book that doesn't work for your Kindle, are you sure this is what you want?" I bet they have some sort of disclaimer hidden away in some giant heap of legalese making it "legal" but the whole flow was clearly designed to trick people this way. And I'm a programmer, I don't get tricked as easily as the average person in this context(I hope).

Amazon is full of minor counts of fraud like this and at their scale I bet it adds up to real money.