Would you expect a school to tell everybody if a child brought a knife into school?
I only know this happened as my dc was in the room when it was brought out of a bag. There was no threat or injury, I think the child was very naive.
So I received a phone call telling me the school have involved the police and are dealing with it. My dc tells me this child has not been in school since.
I am just surprised other parents haven’t been told and would have expected some sort of communication to all parents.