BB guns are ridiculously easy to get a hold of at the war and peace show and the organisers don't appear to have any control over it. Luckily, most people seem to control their kids without any problems arising, but in the campsite, it can be different. I remember when we were 10, my friend who came with us got shot in the face because they thought "he was playing" despite not having a gun.
Did you ask stall holders or exhibitioners what they thought about the war and peace show? It sounds like a huge shame that people decided to leave early. I was hoping to go back next year