* After upload, the Mozilla server checks whether the domain of the IMAP/POP/SMTP hostnames match the email domain. If not, it's quarantined and needs to be checked by a human moderator.
* The server checks whether a configuration file already exists for this domain. If yes, the new one is quarantined and a human moderator needs to check which one is better. (It is possible that the old one was wrong or is outdated.)
The above is just a rough plan, more thought is needed on the details and whether more checks are needed, and how to deal with them.