I very much doubt there's a plain english clause that goes a little something like:

"If we think you have violated (our?) DRM policies, we will delete every book you've ever purchased, and close your current and future accounts. If you think this is done in error, you may not ask us why we closed the account. You may only sue us to get an answer"

To call out a consumer for not being prepared for a no-warning, no explanation ban (and removal of all legally purchased content) seems extreme.