I didn't realize it was to load-balance the different services. I did know that it was for when you GOT to go, not when you HAD to. A long-ago boyfriend's father told me he had been about a quarter-inch too short for the height requirement in WWII, so he slept with weights on his ankles, over the end of his bed, before going to the recruiting center. The walk there shortened him back down, so the next day, after sleeping with the weights again, he had four friends carry him. He served in Italy and had brought back an Italian machine gun as a souvenir. When possession of the gun became illegal, he sawed it in half and made bookends out of it.
One of the prospective original Astronauts was about a 1/4 to 1/2 inch too short according to the regs. Pilots in general are used to being poked and prodded, and measured. But how to overcome this deficiency? On the day of his physical, he took a hammer to the top of his several times, hard. He passed.