If you  specify "Send=a,b,c,d"  it means  a *or*  b *or*  c *or*  d. This
allows  you to  use say  "Send= Private,(STAFF-L),*@DEPT.XYZ.EDU".  Since
PUBLIC lets  anyone in,  the end result  is that anyone  can post  to the
list.
 
  Eric