Mailing-list server programs do include a command
to query on the listmembers. It is quite common.
There would be no problem in triggering such a
query just before posting, and attach the resulting
list and the mail in one file, locally on my disk.
There would be no problem, then to show a print
of this list to a judge, when requested, together
with an alive presentation that the mail can indeed
be read by anyone on court, who is not necessarily
on that list, by simply connecting to the net.
I would like to repeat that I am an old friend,
that I have been posting long before 1998
(not necessarily on Debian), and that my
contribution to this discussion is not going
beyond this list.
So far, only James Miller and Florian Lohoff
have shown a correct reading of this discussion.
An explicit OpenContent agreement is indeed
the way to go.