They can be, but there are caveats. Bringing the kids up at this particular show and tell was a stupid idea. The dog is predictable. The kids aren't.
My vet has a charity dog wash on Canada Day. It's out back of the vet office and HRP brings in dogs for a demo. A Dutch Shepherd and a Lab. Before the dogs come out someone from the vet gets on the mic and tells everyone DO NOT APPROACH THE DOGS. The demo goes fine. Everyone applauds, the dogs go back in the SUVs and leave. No problem. That said, no one ever lost money betting on the stupidity of people. Double that for children.
The story talks about the kid and the dog. What were the other kids doing?
If the other kids were acting up the dog could have gone into a defensive mode, seeing all kinds of unexpected behaviors. Did it see a potential riot by midgets?
The whole story please.