The bookmark is stored on the client-side only, so there's no cross-device functionality present right now.
What I'll love to see in core (a bundled plugin will do, too) is a feature that checks the system for unverified user accounts and either auto-deletes them or marks them for the admin to delete. Perhaps in the Users page on ACP, there should be an unverified users list.
Before we do that, we gotta figure out user deletion first
@julian maybe it's been implemented in 0.7.x, if not is it possible to run the command with redis-cli. Something like: find all "Not Validated" users -> delete.
Check out gh#3507