I've noticed that certain lists "role" accounts are being spoofed (by
viruses) in FROM: fields.  Thus you may encounter:

mail from: listname-SUBSCRIBE-REQUEST@listhost
mail     to: listname-SUBSCRIBE-REQUEST@listhost

Because the particular listname was SERVICE=LOCAL and SUBSCRIPTION=OPEN,
the process succeeded.

I've done a

QUIET SERVE listname-SUBSCRIBE-REQUEST OFF

and was still able to use the auto-subscribe role address (that's a good
thing).

/Pete Weiss @ PennState