It's called discretion. I have some. Along with some common sense that doesn't appear to be so common.
If someone is going to be injured by my lack of reporting an offense then yes, I am a re-****. But, if someone does something trivial, and I go rat them out. Even though the "right" thing to do is report it. There are BETTER ways of handling situations. First off, talk to the person directly, and address your concern with them.
Imagine if every little thing got reported. Nothing would get done. It's not conducive to team play. Those people who constantly ratted people out, did bad for themselves, did bad for the community dynamic, and now no one trusts anyone. Guess what, in health care that's scary. I'd rather the team trying to save my life, collaborate with each other rather than not.
Edit: Try a dental school interview. They ask you questions like this all the time. You see someone cheating, what do you do?
The wrong answer is rat them out. The right answer is to approach the individual in a non-threatening manner. Maybe there's something that lead them to cheat. They couldn't find time to study because they spent the weekend working a part time job because their parents lost their job.
Yeah, it's not right. But a sliver of humanity in someone would empathize and try to help this person realize that cheating is wrong.
Getting someone in trouble, getting them kicked out of school, doesn't rehabilitate.