And I’d be pleased to contribute to that thread, Bearflag. Defamation law is a particular interest of mine.
On preview, to wring: Yep, there’s a tort rule in at least some states that says you can’t set traps for people, for largely the reasons of indiscriminacy you describe. That’s an intentional infliction of harm, which is somewhat different from overzealous self-defense or simple negligence. I could be mistaken in my recollection, however, since it’s been four years since I looked at any of those cases.