Why a balloon is painted on the side of a restroom at the Indianapolis Motor Speedway

On the outside of the restroom in turn 4 at the Indianapolis Motor Speedway there is a balloon painted on the outside.  Here is the backstory.
 
The first race held at the Speedway was not auto, but rather manned hot air balloons. One of the founders of the Speedway, Carl Fisher, had experienced balloon flight in Europe and wanted to bring the national balloon races to Indianapolis. Fisher was always on the cutting edge and I believe if he was alive today, he would be clamoring to experience outer space on one of the SpaceX flights.
 
Fisher was successful in bringing the national balloon races to Indianapolis with nine balloons participating with Fisher as one of the pilots. The day was perfect for ballooning and Fisher believed a large crowd would assemble for the race.  An estimated 40,000 saw the balloons take flight from their downtown offices or their homes but the crowd assembled at the Speedway did not approach Fisher’s hoped for 20,000. The Speedway’s official attendance was 3,500.
 
Many aspects of the preliminary activities at the Speedway are rooted in its history, from the running of the Marmon Wasp which won the first Indianapolis 500 in 1911 in the opening parade to the winner of the race drinking of milk as part of the celebration. As part of the festivities for the 50th anniversary of the first Indianapolis 500 in 1966, the Speedway harkened back to the 1909 balloon race.  If you are scratching your head about the math, while the first automobile races at the Speedway were in 1909, the first Indianapolis 500 did not occur until 1911. Additionally, Speedway closed for racing after the U.S. had entered World War I in 1917 and again during World War II.
 
To commemorate the first balloon race at the track, on the opening day of qualifications, the Speedway featured a two-balloon race with Don Picard, the son of the famous balloonist Jen Felix Piccard and Paul Yost, the first man to balloon across the English Channel as pilots.  
 
The day was windy….not too blustery for the balloon to ascend to the skies…but windy enough to make the repositioning of the inflated balloon difficult.   As the guys handling the lines on the ground were guiding the balloon to its new position, a gust of wind came along and started moving sideways. The men on the ground fought gallantly to control the balloon but couldn’t as it barreled toward a portable restroom….a women’s restroom.   The Speedway had been open for several hours and nature was calling.  The balloon smacked into the restroom toppling it….with two women inside.  Just imagine being one of the women taking care of business when the restroom is, without warning, tipped over.
 
Today the restroom is a permanent structure but the painting on its side commemorates the balloon incident of 1966.  I hope the women inside were later able to laugh about their contribution to the Indy 500 lore.