"LISTSERV site administrators' forum" <[log in to unmask]> 
wrote on 08/16/2006 08:46:14 AM:

> Or the "Precedence: list" header we've provided since 1.8e (14.0).

But do other list management packages insert that header?  I was trying 
for a more generic test. 

It might be easier to get list management authors to add the header than 
all the MUA authors to honor it.