It isn't a matter of ignorance, as the folk were given the infromation
when they subscribed and have been reminded of it periodically, it is
simply they won't RTFI (which I suppose is a sort of ignorance, but it
is entirely self imposed).  There are various schemes for dealing with
this but what they all reduce to, generally, is finding what works for
the list in question.   Good luck.    Douglas [log in to unmask]