http://www.mcvuk.com/news/read/this-is-how-rage-does-the-online-pass
One of the dumbest things I've heard in a while.
Summary:
1) Some singleplayer content is only accessible if you have the access code. If you have purchased the game new, you have it. This means people purchasing used copies of the game do not get the entire product until they then purchase the access code.
2) Said content is not on the disk and must be downloaded. It is downloaded when you find the access point for that area of the game. This means you cannot access that area of the game if you are a legitimate customer until it has finished downloading.
3) Even if you do not have the access code, it still downloads it anyway - despite the game being a whopping 22Gb on your Xbox 360 hard-drive to start with.
Can't *wait* for the 'content download' server to get DDOS'd / be inaccessible due to load / suffer from slow download times..