Behind every leak there is a source. Whether it Windows source code or unreleased games, there is always that small sect of people who seem to get their hands on things before anyone else. Usually, the leaker stays anonymous. In this day and age, however, when release dates and IP are such huge issues, companies will go to great lengths to find who let something slip.
A great example today is Manhunt 2. While some thought it was an enterprising hacker, the truth of the matter is far less interesting. As it turns out, an employee working for Sony in Europe got his hands on an uncensored beta version of the game and began torrenting it. According to the article, said employee has already been fired - not surprising at all, if indeed they were the source of the leak:
"Take-Two Interactive has confirmed that a former employee of Sony Computer Entertainment Europe (SCEE) has acknowledged his responsibility for the unauthorized online distribution of an unrated play-test version of Manhunt 2 submitted for the European PAL Playstation 2 computer entertainment system."
Good? Bad? I don't think it is either, in this case. Software being leaked is pretty much an inevitability in just about all development, and obviously with a game of such hot contention (Such as with the controversy in the U.K.) it is going to be very tempting to be a bootlegger. I wonder, however, if this will prompt Sony to apologize.