How responsible are we for the things we do by accident?
I was recently on the phone with my sister, and she was telling me how she accidentally left the tap on in her apartment, which flooded the kitchen and damaged the cupboards and floor. She was extremely ashamed of herself, but she was even more upset that her boyfriend got angry at her for doing so, since she says she didn't intend to leave the tap running (and I'm inclined to believe her; why should she?).
It's clear she is responsible, in a causal and financial way, for the damages, but is she morally responsible in such a way that justifies anger or punishment against her, despite the fact that she had no ill intent? Or does intent not matter in such cases?