Randy Cohen, who has written "The Ethicist" column in the New York Times Magazine for the last 12 years, just published a new book, Be Good: How to Navigate the Ethics of Everything. He claims the most frequent questions he gets asked fall into two categories: the ethics of the Internet and social networking (should you google someone before a first date?) and also what to do when you become aware of wrongdoing by others. His response to the latter:
The question I would receive the most was duty to report, as a class of question. People who had done nothing wrong themselves were aware of the wrongdoing in others, and they wanted to know when they had an obligation to come forward. The guideline for me is this: When someone is acting in a way that presents an imminent, serious threat to other people, you have an absolute duty to come forward.
So, you would – if you found out that your friend was a pirate and 50 years ago, you know, looted a ship and buried pirate gold, you don't have a duty to the community to set that matter right, to dig up that treasure chest and report your pirate friend. If your friend is about to attack another ship, then you have a duty to come forward.
The Dish 