It has been my experience that some folks REPLY FROM: a different
address than where they are subscribed TO:  E.g., when one
user e-mailed me at [log in to unmask] compared to where they
replied to: from mail received by pmw1, it was different (was
this a badly configured VAX Cluster?).
 
The CONFIRM problem is similar to the SEND= EDITOR, where
EDITOR= userid,(list) and the sender is supposed to be part
of (list).
 
Adding a second (and sometimes third) address and setting them NOMAIL/NOFILE,
as well as possibly NORENEW might help.
 
/Pete