Which is why you should have a separate account for AWS vs your Amazon.com account, and you should download and rip the DRM off your Kindle books.

Part of the appeal of Kindle for me is that I'm really shitty at keeping backups effectively.

Separate AWS account won't necessarily save you - if they can connect the two by name, address, credit card, etc. they're at risk. If you've got a business, having it under the business name might do the trick, but that's still a risk.

You just shouldn't buy drm encumbered things nor trust anyone who might ban you for no reason with no recourse.