I don't expect it'll be hard for the law to comprehend. Sure it's digital property, but unlike a lot of things digital it actually functions mostly by the same rules as physical property (only one person has any given bitcoin at a time, &c).
Even so, maybe, maybe just not a very serious one, assuming we don't write it off as "part of the game".
I picked WoW instead of a game like EVE Online because scamming is not an expected part of the game.
I'm not aware of any criminal proceedings against people who stole WoW gold, but it is an entirely different matter if actual money (i.e. USD) was taken.