LH - on your second point, I recalled the case of the director's son in CA who went on that shooting spree. There were lots of verbal warnings on FB and etc, and the cops were sent to see the guy. They didn't think to search his apartment for guns, unfortunately.

I think checking out verbal threats, even by arresting the person, is a case of better safe than sorry.

If they'd arrested the guy in CA, I wonder if things would have been different?

ETA: And yes, people can be incredibly stupid.