The moral of the story is to never saw your shotgun off a whole quarter of an inch below the legal limit and sell it to some guy who insisted over and over again that you do it, or the short version, never trust a fed.
There was NO negotiating. Are you high? Snipers just took the dog and 14 year old Sammy Weaver before the Weavers knew the Marshals were there. Who researched this?