[GUI Plugin] Kindle Collections
Works in tandem with either Collections Manager kindlet, or librariansync.
Both are hacks that bypass the Kindle UI and thus ignore Amazon's restrictions, in order to directly modify the collections db. Very handy for doing bulk edits based on calibre metadata of course.
That also means the hacks don't enforce a registration check.
The Kindle can display when you aren't registered -- it doesn't delete collections when you deregister, only when you re-register. So once the hack injects collections into the db, the Kindle just goes with the flow.