Reed Me: "After all the Mac v. PC commercials, I will laugh my considerable posterior off if Apple winds up creating a UAC-style prompt to warn their customers that an application is attempting to access critical system components..." - It was inevitable. The kiddies can't resist being destructive. I'm fairly certain they'll come up with an elegant solution, but who knows.
There is one point that's not correct in the post however, Linux does not live inside Mac OS X. It's a Mach Kernel + BSD, which is very, very different than Linux. Inside they call it Darwin, also called XNU.