[Dovecot] Dovecot and quota enforcement - only reporting?

[dovecot at corwyn.net]

I'm currently setting up postfix and dovecot with virtual users 
(mysql), imap, and quotas. I'm setting the quotas using mysql.

I have quotas working correctly, and I can telnet into the imap 
server, and submit
. getquotaroot inbox
and get back valid quota information. I get a maildirsize file in the 
Maildir directory. Very cool.

When I delete mail and expunge it, the quota updates.  However, 
inbound email doesn't appear to update the quota.

Two questions, probably related:
What causes the quota (which I presume is the maildirsize file) to update?
Is there any actual quota enforcement, or just reporting? Because if 
I send mail to an account, even if it currently reporting (via 
maildirsize or . getquotaroot) that the user is over quota, they 
still can send and receive email.

Thanks!

Rick


Rick Steeves
http://www.sinister.net

"The journey is the destination"