Polo Rules

More refs should call high sticking, it's the most dangerous thing still permissible and >allowing it on shots seems counterintuitive to me (as being hit in the face by a shot is >probably going to hurt more than most other times mallets go above shoulder height).

There is a logic to it. Banning ball/puck contact over the shoulder is an easier way to make the game somewhat safer, without greatly affecting the game. But if you force the shooter to think about their shot in that way, it's going to affect the game much more.

It's exactly the same rule in Hockey. You can raise the stick on the backswing, but can't contact the puck above the shoulder.

The NHL and other leagues, and even beer leagues enforce visors to deal with the majority of the backswing issues.