The rally commemorates the repeal of the act which required a self-propelled vehicle on public roads to be preceded by a man waving a red flag. ( some say this is nonsense since this applied only to vehicles towing three trailers or more.
But it could have been worse -
" In the United States,...... . the most infamous of the Red Flag Laws was enacted in Pennsylvania circa 1896, when legislators unanimously passed a bill through both houses of the state legislature, which would require all motorists piloting their "horseless carriages", upon chance encounters with cattle or livestock to (1) immediately stop the vehicle, (2) "immediately and as rapidly as possible... disassemble the automobile," and (3) "conceal the various components out of sight, behind nearby bushes" until equestrian or livestock is sufficiently pacified.[1] The bill did not become law, as Pennsylvania's governor used an executive veto."
Wikipedia is not always 100% accurate, but I hope this one is true
