Figuring you know the what so maybe you know the why. You often know more than most.

[edit: why the heck are people voting mikeash down, legitimate question after all in tone and spirit]

I'd speculate that access() was inadvertently left open before, Apple subsequently sandboxed it, this broke Blizzard, and Apple put in an exemption for them to avoid breaking millions of people's games.

But that's a complete guess.