WolfEdge said:
There's a psychological theory at play here. It's called "Diffusion of Responsibility".
I'd look it up and give an exact definition, but I'm sweepy...
I think this pretty much covers it.
When I was younger, I liked to think that if I was being attacked that someone would step in, that someone would help, but I'm no longer naive enough to believe that. If someone was being attacked most people would just pass it by, out of fear, out of not wanting to get involved, out of thinking it's none of thier business/ responsibility.
I'd like to think that in similar curcumstances I would try and help, I like to think that I'm a better person than this, but since I haven't been involved in anything like this, I'm not sure whether my flight instincts are stronger than my fight instincts.
EDIT:
I think this ones a bit better.