How about a teacher's perspective?
I don't post around here much - just lurk and soak up all the valuable information to be had. I'm 27 and a teacher (of music, believe it or not) in Ohio. I've been an armchair commando since I was about 6 - I could rattle off facts and statistics about every gun I'd ever heard of. I now own several, pistols and rifles, and plan to add a few more before I'm done. I was happy that Ohio passed CCW laws, idiotic though some of them may be. Just for the record, my mother tried very hard for several years to keep me from playing "army" with my friends, feeling that I would grow up to be a psychopath, but I still turned out OK
I teach in an inner city school district where a gun showing up on premises is a distinct possibility, though I've not heard of it happening since I started with the district three years ago. All schools in the district have the sticker on the door prohibiting guns on campus. The idea is to promote a safe environment, whatever that means. Yes, it would make sense to teach all students about gun safety, and to impress on them the danger that's associated with handling firearms. However, I have students from such incredibly different backgrounds that this would be impossible, both from the attitude and the performability perspective. The general feeling is just not to bring the idea up at all.
To be honest, the teacher above seems to be concentrating on a non-issue. But on the other hand, sometimes we get tunnel vision. We spend so much time being psychologists, cops, and surrogate parents, that sometimes when we mean well we complicate an issue. We're people too, you know.
And JohnBT probably grabbed the brass ring on this one; in my district, principals have the power to set a lot of discipline policy within their own buildings (and inside district guidelines of course). There's a real good chance that the powers that be at the preschool in question have decided that the "hand"gun is a no-no and must be addressed immediately, and the teacher is simply following her own rules (we've got them too after all).
Don't know if that helped anyone's perspective, or even made sense (it's late here and I'm fading) but that's my humble opinion.