Yeah, but teaching knife safety (and gun safety, too, come to think of it) is not at all the same as letting people "play with" the weapons. And martial arts dojos teach preteens and teenagers weapons all the time, both defense against and using them themselves. They don't start with actual sharp edges, as far as I'm aware (so Matt still wouldn't be touching the actual knives).

And yes, I know, Frank Castle isn't remotely a teacher. I just thought it could be kind of fun. It was an "eventually" that no fic would ever actually get to, anyhow.