[Dovecot] Immutable Maildir (or: "I know drag&drop")

Hi,

I'm 'constantly' (every odd month) faced with users happily dragging around or (un)subscribing folders in our shared IMAP account. Is there a "clean" way to prevent users from doing that when having a Maildir?

Unix permissions probably won't cut the slack since setting any Maildir (sub)directory to readonly (immutable or chmod u-w ) will probably cause dovecot to hit a wall at high speed sooner or later (lock files, rotated cache/log files)

Got any other ideas?

best regards, Michael Renner