If everyone has seance of the obligation of witnesses, we don't need the law to force people follow it, but from the article we saw, I think it will be helpful for reducing the crime if the witness know they have duty to report it.
It is not the first time I hard about Kitty's story, but it is the first time I read the full story. I just cannot believe that no one want to stand up for her even just a call, how cool those people are. I feel sad about how people are selfish and cool enough that they can watch people die in front of them just because that victim is a stranger. I would say we don't have right to force the witness to do what our society expect them to do, but if a person has compassion and think himself as a good person, they should feel guilty when they do noting and put someone in death. I believed that if the human beings' moral justice cannot let them have acting when facing crime, then we need to create law to let people aware what we should do.