When I was at a game in Calgary, I happened to actually READ my ticket stub. It's printed on it that, by buying a ticket, I absolve the NHL, or the associated members of any responsibility for injuries that may occur should I be hit by any puck etc. while watching a game.
I had no idea......................but I stayed and wasn't hit by a puck etc. By merely attending, you are accepting the possibility that you may suffer an injury. Hmmmm...
You get the same at a baseball game for balls, bats, and misc. items leaving the field and going into the stands.
Pure boilerplate, often thrown out by courts, but not always...