You may send the user a message to request further information. Users may unsubscribe at any time without moderator assistance. If configured, remote administrators may view or search the subscription log. This is a file that contains all changes in the subscriber database, one per line, in order of occurrence. Listing this file allows the remote administrator to see recent additions and removals.
Remote administrators can also search through the log.
The search is case insensitive. This feature is useful when a user wants to unsubscribe, but has changed his address and doesn't remember the subscription address. Just search for the host name, part of the user's name, etc. Usually it is obvious which of the few alternatives is the correct one. Construct an unsubscribe request from it, and if you are right, the user will receive a request to confirm the unsubscribe.