I had a coach bail me out of an accidental whistle earlier this year in a freshman game. A1 is bring the ball up diagonally with B2 beside him. B2 has his hand on A1 but in no way is hindering his movement. All of a sudden, out of nowhere, I feel a sneeze coming. I sneeze as I am spitting out and there is a little "tweet". Coach yells, "I told you to keep your hands off him!" I think, works for me, and report the foul.
So...still only one accidental whistle in all my games
