Probably one of the most powerful learning techniques is putting a good man in front of a group of peers and have him explain how he came to make a mistake. Organize a structured discussion on the contributing factors and possible mitigating measures. We then all walk away more aware and safer.
Lifting the maker of an honest mistake out of the system and dumping him/her by the wayside will have no beneficial effects whatsoever. Quite the contrary. It demonstrates short term focus and a lack of vision and commitment to systematically improve an operation. Not to mention the destruction of a transparent reporting culture.