Lists frequently erupt into flames about posts in HTML.
MUA's will often respond to an HTML message by replying in HTML, perpetuating the problem caused by an initial HTML post.
Even users normally posting plain text often slip up, particularly when mailing from other than their normal host.
HTML needlessly eats up to 3 times the storage space for messages in archives, worse if the message is in both HTML and plain text.
Mailman needs an option to enforce plain text posts by detecting and rejecting posts in non-plain formats, particularly HTML.
The sender should get a polite, canned note to turn off special encoding and re-format their posts in plain text. The note should be customizable so that instructions might be included for how to do so for common MUAs.
Please consider adding this feature.
(I'd asked about this a long time ago, but I never saw any comment on it.)
George Nemeyer Tigerden Internet Services