1908, Theodore Roosevelt
Oral tradition passed on through multiple generations holds that on June 14, Theodore Roosevelt was dining outside Philadelphia, when he noticed a man wiping his nose with what he thought was the American Flag. In outrage, Roosevelt picked up a small wooden rod and began to whip the man for "defacing the symbol of America." After about five or six strong whacks, he noticed that the man was not wiping his nose with a flag, but with a blue handkerchief with white stars. Upon realization of this, he apologized to the man, but hit him once more for making him "riled up with national pride."
Thanks to Julie Golob for the pointer to this interesting (and probably apocryphal) bit of historical trivia.