> What if an owner experiments with NOPOST on his/her own subscription?  Who
> can then modify the setting?
 
Any owner can, including the one set to NOPOST.  NOPOST only blocks
messages intended for distribution to the list, it does not block
commands to the Listserv.
 
> Second, is there a generic test list that owners can "play" with; change the
> password, the header, set ficticious-subscribers' options, ...?
 
I don't think there's any such "test list".  I suggest that when you get
a new list, that you do all of your experiments and exercises *before*
opening your list to the public, so that no harm is done when it might count.
 
-- Roger Burns    [log in to unmask]