One positive — crazy teachers would HAVE TO HAVE AND KEEP HAVING sanity checks. They just would. People wouldn't want teacher going nuts. Teachers don't have flawless name; they're as associated with rape as priests are.
So leftyfag teachers couldn't get guns, and it's overall good solution.
OTOH, all it takes is ONE flipping, mowing down classroom, and idea wouldn't sound so good anymore. Until we know CIA/FBI not mindfagging people, not sure I'd be comfy with somma teachers I know who do range thing being one of few with guns. People do flip.