Should justice require common sense?

I just read this article about a 4 year old being sued for running into an elderly lady.
Yes, this is a sad case. But are we to be held responsible for every accident that happens. Even when we do our best to prevent them.
If that is the case, than the old lady was a risk taker. She walked outside her doors.
Should we all be put in a glass bubble?
Isn’t an accident simply an accident. I’m sure the little girl had no intent in ramming into anyone and potentially hurting anyone. I once ran over hit a ditch and it slammed me into a pole. Should I sue the pole or the city for the ditch.