Did that once. Had a coach screaming for a personal foul for what looked like a late hit. From my vantage point, it wasn't. Coach was running out of the team area screaming. I threw the flag for USC. Coach said "Finally!" He went to attend to his player who had been injured on the play. When he turned his attention back to the field, he noticed his offense had lost yardage. He asked my white hat why. The explanation led to coach going ballastic and getting his 2nd USC and the trip off the field.