OR maybe they put all the content they have finished up to making the disc but it was not 100% complete. When the DLC comes out they will patch the missing pieces. So there is extra locked content on this disc but it has not been fully completed. Leaving it on the disc will make a much smaller patch size later on when DLC is released. It is not like when the game was sold they had no clue what DLC they would like to introduce. I am sure someone has been working on it for moths. So why not include what they had started on the disc?