DRM-free Kindle books: are they any free-er?

Amazon is selling Kindle books without DRM, but they still won't answer three fundamental questions: 1. Whether the terms prohibit moving DRM-free books to non-Kindle platforms; 2. Whether patents or other IP prohibit making third-party readers for the Amazon DRM-free format format; 3. Whether they can still revoke DRM-free files, or disable their features, and if so, which features can be disabled and what circumstances would lead to revocation. The answer to these three questions is the difference between owning a book and having an innocent book used as bait for a tawdry lock-in scheme.