I registered for one of these things weeks ago. Still haven't got it.
I think you answered why though, I don't have a 1-year XBL membership..... yet.
I also didn't put the right info (DOB, etc) so that wont work either.
I didn't know what it was, I just thought it wasn't an online thing. I didn't know they were sending me anything until I clicked submit.
I will re-order one once I get my 1-year Gold membership.