That would be scary if the kid brought an arsenal of explosives, such as potassium perchlorate, sulfur and antimony sulfide or of red phosphorus and potassium chlorate. I think this principal would have wet her pants instead of doing that to a little kid.
School chemistry classes in my day could be characterized as explosives. A teacher one day blew a panel out of the ceiling in a demonstration to our class.
Also reminds me how one kid in our class used some magnesium ribbon or something from the chem lab, stuck it in the classroom door, lit it and melted the keylock inside so we couldn’t get in class after lunch.