I don't doubt it Possum, I know that in a 'small scale' for want of a better word crime, people have and will take action to protect themselves and others.
My interest is in one of these horrible mass attacks, when there are large numbers of people involved. I know that groups as a whole are far slower to react than individuals, there is always a delay while a leader or first mover appears. It is a question as I say of genuine interest, because I don't recall any, but then I haven't studied it that hard. I suppose that is why soft targets like schools are often chosen, because they know that there wont be many/any? People carrying.