Here are two golf rules: (1) if you hit a ball as it begins to move, it is a one stroke penalty, and (2) if you sign your scorecard with an incorrect score, you are disqualified from the tournament. During the first round of the British Open, David Toms believed he putted a golf ball that had begun to move. He said nothing. No one saw it. He signed his score card without including a one stroke penalty.
The next morning he tells course officials what had happened and voluntarily disqualifies himself from one of the biggest golf tournanments of the year.
I love stuff like this.