Menachem > “Am I doing this in order to help/save/protect that person/others, or just because I enjoy being a snitch and getting the guy in trouble?”
Indeed. I just asked a shailah about whether to tell another person about something that is happening with his property, and the Rav re-phrased the question – so, what will be achieved by saying that? So, the action is justified by the expected outcomes (to be more precise by probability distribution of expected outcomes).