An elementary school kid on a unicycle? It’s more common than you think.
Actually, in Japan, one of the things taught in elementary P.E. class is how to ride a unicycle. Along with the ‘normal’ sports of soccer, baseball, basketball and volleyball, kids learn about ping-pong / table tennis, stilts, swimming and as I mentioned, riding unicycles. Oh, and badminton.
Who’s worried about a scraped knee?