I believe that any subscriber's distribution option that
has FULL at the beigining e.g., FULLBSMTP will generate
such a header.  This can be controlled 4 ways:
 
1) user changes subscription option to something else e.g.,
   SET list SHORTBSMTP
 
2) same as 1) but list-owner effectuates change
 
3) list's default-option changed for _new_ subscribers
 
4) add/replace list's keyword
   NEWSGROUP= to be something other than the default (BIT.LISTSERV.listname).
 
/P