Official Mailing Lists

At our web site page for joining mailing lists, we have a section titled "Mailing List Etiquette." Should we expand that section with a short policy statement about expected attitudes? I don't want to discourage healthy debates and discussions, which always will include a wide range of opinions, but if we post a policy we establish nominal knowable boundaries and basic CYA. Perhaps in list messages we could add a reminder sentence in the footer with something to the effect about thinking positively and not to attack the goals of other projects? Just thinking out loud with respect to our recent "damage control" discussion... Darrell