I have never understood how any school could ever feel confident in saying they are safe anyway.  You cannot seriously expect teachers to be able to police every food item kids bring.  The thing I don't understand is that you would not be allowed to bring packaged cookies, for example, that are not made in a "nut-free facility", like some cookies are.  OK, you could see that on the label.  However, my kitchen is not a nut-free facility.  Which means any food I send has now not come from a nut-fee facility.  My own baked cookies, even nut free, went through my kitchen.  The apples in my fridge came from the same non-nut-free facility.  So how is anything safe?  Mars Bars are ok because their facility is peanut free, but a sandwich I made out of ham and cheese in my kitchen would not be.