Some say "yes", that you have to report a serious crime rather than just not participate. I'm not sure what the situation is with a refused bribe. Modern life sure is complicated.
Nothing complicated about this. If Zero saw a crime going down and failed to report, that is a crime in and of itself. There have been a few threads about that these past few days.
Misprision of felony
Whoever, having knowledge of the actual commission of a felony cognizable by a court of the United States, conceals and does not as soon as possible make known the same to some judge or other person in civil or military authority under the United States, shall be fined under this title or imprisoned not more than three years, or both.