There are plenty of extenuating circumstances. For example, if you were a spouse of a corrupt law enforcement officer who's already facing domestic violence, would it be racketeering if you did not report your spouse's conduct? I am willing to bet it wouldn't (you have a credible fear of being assaulted, or worse yet, losing your life if you did so).

This is why things like anonymous tip lines and whistleblower laws exist. You are encouraged, in general, to report misconduct. But there are very specific situations where it's illegal to not report misconduct.