There's at least 50 level 30-55 naked dwarf and orc hunters (without a pet) running in and out of Stratholme on my realm atm. When they come out of the instance with minimal hp left, they stand still for 10 secs, then fly up and through the tower at least 3000% faster than a flying mount and vanish. So hacks are definitely included.
I checked a few armory profiles and they all have "Got My Mind On My Money" achievements as high as "Loot 5000 gold", yet they all seem fresh characters. No achievement is older than a couple of days.
How can they make that much gold in Stratholme? Chests? At least naked chars can't kill things there. And selling stuff in the AH doesn't count towards that achi afaik.