After listening to the B-12 Actual Play--and again, kudos to Tom for cooking up a great CoC story--I've gotta say, I think that Aaron's problem has been misdiagnosed. He's not a boy scout; he obviously has no problems with his character lying to the police and other officials in order to accomplish the mission, and he had no trouble calling off the neighborhood development project when the ghouls paid him a little visit in the night. He's simply a bit too naive to think of the consequences of his actions. And what better forum to gain valuable experience in this area than in the virtually consequence-free environment of roleplaying? Once again, in terms of GMing, Aaronisis is only a problem insofar as it interferes with a storyline, which is to say, only as long as a GM allows it to arrest the flow of a game's progression. I think Tom could have made wonderful things happen if he'd decided to depict the potentially lethal consequences of giving a serial killer your business card if Ross hadn't pushed things forward after the mugging scene in the alleyway.
I know I sure as fuck wouldn't want Grady knowing where my CoC character lived.
So I guess my revised prescription for Aaronisis is to let the afflicted experience the consequences of his or her actions. Eventually, they'll get the point and adjust their playing style to avoid being eviscerated by the nice, friendly mass-murderers they try to help out.