hacks and bots
100% always gaurenteed to be server hackers and botters and/or some exploit when ever you see people gearing or max level within hours of launch and it's not from the auction house
don't worry
blizzard will ban them all like they have been doing for years
blizzard has banned thousands of them over the years and they usually never get their account back due to flimsy excuses on how they did something the game wasn't programmed to do and/or something your body wasn't made to do (being awake 24/7 for an entire week to level up for world first) usually they had multiple people playing their account if it's not a bot program