OK, this is the reverse of what most people complain about...

I have a user who does NOT want a copy saved to her Sent Items
folder. "Save copies of messages in Sent Items folder" is NOT
checked. She says not all messages get a copy in Sent Items, but
some do. I'm still waiting for a response on whether we can tell
what may be triggering the save, like doing a reply/forward versus a
new email, etc....

Outlook 2000 with SP1 and Exchange 2003 SP2.