Has anyone figured out what the Unlock Code is for? It fits the registration format on SE's website, but it says its an invalid code. However I got my free month, CE items, everything possible, from the registration code. I've pretty much written it off as something I shouldn't care about, but still curious what its deal was.

Maybe it's like the original Diablo 2. How it came with a 4 Disk case, but only 3 CDs. Confused so many people when it launched. Might be one of those quirky things that is just there.