I watch some clips about it I thought it was just for fun but didn't know that it was really a competition, just come to think of it receiving a direct hit on the face if they get it like most of the time I'm sure there will be in long term there will be a great consequences with that. I really don't think this is some kind of sport at all.
Dude it's the same damage with boxing, I mean look at Ali, Roach and other fighters who suffered from Parkinson's Disease. So what's your point? That it's a direct hit to the face? Boxing and other fighting sport will more likely cause you injury than slapping plus most of the tournaments have mouth guards to protect the player from concussion.