Damn right it's not my problem, that doesn't mean I don't act on it. Your sweeping statement was that it is my responsibility for a stranger although in no way had I caused the problem.
I'll help because I want to help, not because I have to help someone.
So how does this work then,
You'll help somebody if you had caused the problem, and/or if you want to help someone?
Surely everyone has the moral responsibility to help everyone else if they are in need, that morality isn't based on guilt or wanting to do something, but doing something because it is the right thing to do.
Obviously people have different interpretations of the right thing to do, but I'd have thought that the basic principle was common.
The rest is a matter of opportunity, almost nobody goes looking for people to help, but if you fall over someone then as the first person there I'd suggest you have a moral responsibility to be helpful.
I think it was somebody else that suggested biscuits
@Angilion, not N/S, Northern/London, big difference and a common enough perception from those that have worked there, I'm not saying anything special here.
@moogle, by responsibility, doing a bit more to check she was physically OK, not just to hide behind the curtains and ring the police four times.