But IMO, the list processor software is a recipient as far as the
internet mail system is concerned. (You get a final delivery DSN when
the message is delivered to the mailing list processor.)
Let me put it differently.
A sender should either expect the recipient to use the label, or else
put in application/octet-stream.
no, I don't think so. the sender should label content clearly, so as
to inform the recipient and his MUA. the recipient and his MUA then
make use of that information in deciding what to do with that
Saying things like "the label is useful and should be there, but only
human recipients should use it, programs should ignore it" is IMO
I don't think anyone's saying that. clearly the label is there so that
the recipient's MUA can use it.