Why not treat vacation insults like persistent delivery problems?
In other words, automatically unsubscribe the perpetrators.
How about because the vacation message came to you, the poster, and
not to list administration? You've got a third-party trust issue right
there.
Once upon a time, "automatically" did not mean only "by computer and
untouched by human let, leave, hindrance or even oversight." I was
thinking of such as the so called "automatic suspension of driving
priviledges" that drunk driving convictions or refusals to take alcohol
tests cause in some places, say by sending copies of vacation messages to
the human administrators of IETF lists.
If you want something purely computer-controlled, how about using
vacation responses to the regular "IETF List maintenance" messages
from ietf-secretariat(_at_)ietf(_dot_)org and the announcments of the filtered
form of this list?
My theory is if that vacation noise were known to be reason for
involuntary unsubscribing or just likely cause for public humiliation,
people would exercise a little care.
Vernon Schryver vjs(_at_)rhyolite(_dot_)com