This is NOT a piracy question, I'm simply curious as to why this is. What is it about the OFFICIAL Nintendo discs that allows them to read, but avoid a copy of a disc that has the exact same data? Is it the way they are burned at Nintendo? A size difference in the discs? Some sort of invisible code somewhere on the disc? I've always wondered how the Wii distinguishes between official and non-official discs, and why we haven't been able to burn "Official" discs, essentially for any console.

So what is it about these discs that are so special?

I think that the discs are printed, meaning they are made with the code on them, rather than burnt from a DVD-R.
I think that allows them to create something unique that cannot be replicated by a normal DVD burner. However other companies like Datel could, as demonstrated by its freeloader while the trucha bug was in place.

[debugmo.de]