It's a catch-all term that allows Blizzard to justify whatever they want, because they are the only ones who can define what it means. Users try to tell Blizz what it means by saying boxing goes against it, but that's just silly because currently Blizz has stated that it is not against the spirit of the game.However, some Dev could decide boxing is against the spirit of the game tomorrow and there's nothing we could do about it. Blizz defines the term by what goes against it, without limitation, which allows its meaning to be ever-changing.