If anyone wants to spend an hour or two reading up on some history of anti-cheat software in MMOS, and why SE and others have such a hard time automating the detection of bots 'n such, I'd do a few googles about WoW and Warden (the software, not the faction).

Long story short: It's very expensive, and it's a constant battle. Not nearly as easy or cut and dry as you'd assume it would be. Still very interesting reading, though.