You have more experience with children than I do, but again, I have to respectfully disagree. There's nothing wrong with imagination play, and theirs nothing wrong with imagination play involving imagination bombs. But there is something wrong with telling someone not in on the imagination that you have a bomb, without making it extremely clear that it's imaginary. Even for 5YO's.
Respectfully, a child does not have to make it clear.
He's 5. Children live in their own worlds
and that's a good thing. It's on the ADULT to ask something like: "Oh, ok. That's very dangerous. Now, is it a real bomb or a pretend bomb?" And, if they are still worried, they say "Okay. Now you need to make sure to say "pretend bomb" because there are bad people in other places of the world that DO put bombs in children's backpacks and we want to be sure you are safe."
It's ADULTS who are supposed to be adults and, first of all, understand the difference between pretend and real
1 and, secondly,
appropriately guide a child about appropriate behavior
2. They did neither. They pulled out the rule book and shirked all responsibility onto "That's the rules!"
We have adults who never want responsibility. WORSE, they are the ones we entrust to teach our children.
1: Failed here.
2: Oh, hey, they failed pretty spectacularly here, too, given that we are discussing their over-reaction. They were trying to teach about appropriate behavior by showing exactly what is NOT an appropriate reaction.