It's a small martial arts world. Check out Jean Claude Van Damme as an extra in the original Karate Kid at the All Valley Tournament. (seated on the floor in the black gi during one of Bobby's fights)
It makes sense seeing as Jean Claude came to Hollywood in 1982 from Belgium in search of movie stardom and the Karate Kid was filmed in late 1983. He was probably dialed-in to the local LA martial arts community and heard they needed extras for the tournament scene.
He was most likely hoping to get a fighting scene and I can easily imagine him approaching director Avildsen about it but upon seeing the kid's skill Avildsen probably didn't want anyone showing up Macchio and Zabka. (although Vidal actually did that anyway)
Still, Jean Claude in the Karate Kid. Epic!
