If they threaten violence they should be institutionalized.
Who reports them? Who orders them institutionalized? Use the Uvalde case as an example.
Well the shooter was out to shoot people and it didn’t matter who - evidenced in he shot his own grandmother first - then two people in front of a funneral home after he crashed the truck - then he fires in the school parking lot .......all this BEFORE he entered the school.
Not so sure this shooter could have been stopped by Institutional living prior. His home environment certainly would have been questionable in supporting that. And I tend to think the community likely see other students very similar to his behavior in their school system.