uol.com.br is now banned from this list

[gb spam]

On 11/17/05, Warren Togami <wtogami at redhat.com> wrote:
> Hmm, I forcefully unsubscribed everyone with a @uol.com.br address, but
> I am still receiving those damned petsupermarket bounces immediately
> upon sending a message to the list.
>
> uol.com.br has been a problem here for months.  This is insane.
>
> Warren Togami
> wtogami at redhat.com
>

How big is the mailling list?  Is it possible to send an individual
email to each subscriber that has the destination email in the title? 
Then, when it bounces back you'll know who's the culpret.  Obviously
this would impact all subscribers, but anyone who posts to this list
would be more than happy to get it.

Perhaps the email could be a warning that people don't use email
addresses associated with challenger/response systems.

If this is too drastic, perhaps it could be implemented in the mailman
reminders?  A bit of work presumably, but worth the payoff?