There is also a variation of that old question "If a Tree Falls in the Forest, and Nobody's There, Does It Make a Noise"?
For firearms it goes "If you carry a firearm Concealed, and nobody see's it(or knows it's there), was it really there"?
I sure love my Kel-Tec P3AT for just that reason.
Just remember you are around kids.....who may be close contact.....hugs, grabs etc. Concealed means concealed from view.....the kids may be doing more touching than looking depending on what your kids class is like.....
Best bet from one who is in the schools regularly, and managed to get OC actually taught in one class..... go unarmed, be the model parent, help out whenever you can, however you can, and take the opportunity to sound out the teacher, and present good news articles.... say did you hear how (kid, parent, teacher, storeowner) saved _______. Good thing he was armed!. Teach the teacher, and they will teach the others....