Turning one's back on a wrong note

When a high school musician flubs a note during a rehearsal, the conductor will usually ask the player's section to correct its intonation.  Sometimes, the conductor will speak to the individual player.  I once saw a conductor try a more unusual tactic, however.  When a bassist played a note out of tune, the conductor stopped the orchestra and said, "I don't want to know who played that note out of tune.  I'm going to turn my back.  While my back is turned, would whoever did that please make a note in his or her music?"  After a short pause, the offending bassist exclaimed, "It was me!"  As the orchestra burst out laughing, the conductor, while starting to chuckle slightly, told him, "I said I didn't want to know!"  To the conductor's credit, his unusual strategy worked.  The bassist played the note in tune from then on.