The worst thing that could happen to me is that I could have my Amazon account terminated. Everything physical on Amazon gets slapped with an additional $60-80 of taxes (even if the item itself is $10-$20), so I really don't use Amazon for anything else but its bookstore.
Books take months or years to write, and I want to award that behavior with whichever percentage of my $10 ends up in the author's pockets. Don't get me wrong, if I see a book I want to read on Humble Bundle on Kobo, I'll click on it first. But if I don't, I'll pick Amazon over Google Play Books, this Microsoft's one, or any other DRM-enabled store. Not because Amazon is in any way better than them, but because I know I can break the DRM effortlessly and reliably, while still pitching in something to the author. If that wasn't the case, I wouldn't look for a different store — I'd still be pirating.
I said publishers but i am not sure who wants this to be enforced in this case. Its just usually the case that its the rights holder like film studios or music labels but in this case i could see amazon wanting it for themselves too.
Just saying, you probably could directly pirate the books too. Putting your money where your rights are respected and you are given the freedom to read your books on any device you want is probably a better idea. Even if it is just to make them grow more.