Problems with moderated and unmoderated groups on nonstandard setups

From Paul Schleck:

- At least one news service provider, Usenetserver.com, may cause
  problems for a newsgroup that is inconsistently listed among servers
  as both moderated and unmoderated.  They will forward to the moderator
  submission address any post to a moderated newsgroup that reaches
  their server without an Approved header, even if it originated outside
  their domain.  This is clearly inconsistent with established Usenet
  protocols and best practices, and will cause duplicate submissions,
  but I have been unable to get anyone at Usenetserver.com to
  acknowledge and act on this misconfiguration.  Usenetserver.com
  resells its news service to private-label ISP's, so there is the
  potential for many, many origins of misformatted submissions causing
  duplicates.  Over on rec.radio.amateur.moderated, we noticed this when
  we started getting duplicate submissions.  Someone or something was
  reinjecting our articles without an Approved header, and they were
  getting mailed back to us.  Procmail configuration allowed us to trap
  and report them, but it was still a hassle.  We were finally able to
  reach someone at the ISP that was using Usenetserver.com as its NSP,
  and put a stop to the duplicates.  See:

  http://groups.google.com/group/news.admin.net-abuse.policy/msg/a62e29151474aed2

  but that only stopped them at this particular ISP.  Another ISP could
  cause the same problem as the Usenetserver.com bug is still there.