> List-Unsubscribe:mailto:LISTSERV@host?body=unsubscribe%20listname
>
> Where is adding headers documented, so I can check pro's and con's.

They are called "banners"  top and bottom banners .. and are in the MAILTPL

If your host has version 1.8d the absolute easiest way to install either top or bottom
banners is via the web page listowner interface and the listowner manual will give you
the special formating and other info for them.

    . ..Cleo  [log in to unmask]
UnOfficial Listowners' Manuals/Guides/Tutorials
http://angus.interspeed.net/listowner/