[Dovecot] Disallow folder delete

[Kenneth Porter]

Is there a straightforward way to disallow the deletion of all IMAP 
mailboxes?

I have a user who's deleted an important IMAP mailbox and I'm now 
recovering a recent copy from the backup. But I'd rather just blanket 
disallow all folder deletions.

The user is using Thunderbird and this has happened more than once so I 
suspect Tbird is willing to let a folder get deleted too easily. Perhaps 
there was a delay in the confirmation dialog and the user clicked ahead and 
confirmed something he shouldn't have.

I'm looking at <http://wiki.dovecot.org/ACL> and it looks like I should be 
able to use a group override to disallow "x" (mailbox delete) but the page 
says that groups aren't implemented, so I don't know how one says that 
nobody can do this for any mailbox.

I'm using 1.2.rc15 from CentOS 5 (RHEL5 equivalent).