Problem with this "live by our rule or die" approach is the fact that many apps for the Mac, we love so, because they disobeyed the HIG. And I don't necessarily mean extreme apps like Shapeshifter, but take for example the HIG saying don't create your own menu bar extras. That's reserved for the System. We completely shrugged that off and created our own menu bar extra-apps anyway. If there was (run with me on this) an App Store for the Mac; then apps like Quicksilver and Twitterrific would have been turned down.
Other excellent apps which breaks the HIG in this manner are:
And this is only one way in which the HIG in not followed in these applications. I am sure there is a slew of other ways as well. Developers break these guidelines, sometimes for a reason, sometimes by mistake, sometimes because the HIG simply did not describe a specific use case.
This is when the HIG are getting dangerous: They have become not only law in the sense that virtually everyone and their blogospehere mother were screaming for Apple to follow their guidelines. Now the same guidelines are the arbitrer of good applications for the iPhone. It is law.
Not to mention games. They are their own mini-environments with custom user interfaces.