Just like 2pac
I've often speculated with the missus that he faked his own death because he knew he was finally in too deep what with 50 concerts at the O2 in London (of which me and her were attending one, spookily on the day he was buried).
However, it might make sense for the album to be released on another day for impact's sake, but I'm not really sure how it works with stuff like CD production and such. I don't know if they set a deadline with the factory that produces them and then have to stick to that, or what, but it could be as simple as saying, 'Ok, let's get it out there a week earlier'.
Obviously, that'd be a bonus for us fans too.