Pushing back in Sydney on the way to Seoul, I was astonished to see several large, hairy Australian ground-crew lined up waving the flight off. It happened again, all the way to Seattle, and back...
Certainly not an Asiana exclusive. It happens all the time at YBBN with a number of carriers/ground handling service providers. One Qantas LAME has a santa hat to wear at Christmas for his wave.