User blog comment:-Saryn-/Nen in Heaven's Arena/@comment-14902757-20140303022458

This is a really good question... this has never crossed my mind tbh. But I'd imagine that it's only a problem when 2 emitters or 2 transmuters are fighting, or emitters vs transmuters vice versa. Abilities in other nen categories are visible to the normal human eyes. If there were emitters and transmuters fighting however,  they still need to engage in an actual combat because the stage is rather small. I'd  also imagine most fighters in the heaven's arena to be enhancers because of their nature. If one has learned nen, it's not really a profitable idea engaging in fights all the time. Fighters who have just learned nen when they reached the 200th floor must have learned about their nen categories too late and just decided to go on fighting without considering the usefulness of their powers in other fields. One would rather use it in more important or more useful things. Plus, you're right about the spectators having accepted that at 200th floors and up, people use extraordinary abilites. About Killua and Zeno's Dragon Dive, I think I answered it here: http://hunterxhunter.wikia.com/wiki/User_blog:Lifebleedin/how_does_killua_know_zenos_ability