mailbox.mbox.add() appears to set both access and modification times

[tinnews at isbd.co.uk]

I'm using mailbox in Python 2.5.2 to filter incoming mail into
separate mailboxes.  I prefer mbox for various reasons and so I have
used that format.

It would appear then when I do:-

    dest = mailbox.mbox(destDir, factory=None)
    dest.add(m)

it sets both the access and modification times of the mbox to the date
and time now.  This is a disaster for MUAs that detect new mail by
looking to see if the mbox has been modified after it was accessed.

Is this a known bug in mailbox.mbox.add(), or am I doing something
wrong, or what?

-- 
Chris Green