It seems that Valve doesn't always need a thief in order to have its "Top Secret" material leaked to the public. Just weeks before Half-Life is set to go Gold and about a month before the game's release, the prestigious developer has made another mistake which could potentially reveal H-L 2s surprise ending, even before the game becomes available.
According to the latest information, Valve's blunder was a result of the accidental upload of a file containing every bit of dialogue from H-L 2, to subscribers to Valve's Cyber Cafe program who were Counter-Strike: Source beta testers.
In theory the dialogue would be hard to access since it is embedded in a .gcf file, delivered by Steam. since .gcf files are not easily accessible, Valve may have thought that the dialogue was safe. Unfortunately for Valve, various gamers have used all means at their disposal, including the previously leaked H-L 2 source, to extract the dialogue from the .gcf file.
The matter still remains a mystery since Valve has not yet confirmed the leak. This is, in-part, a result of the limited distribution of the offending .gcf file, something which is very good news for Valve since the matter became public before more people got hold of the file.
Since a couple of days have passed since the original leak, it seems that Valve may have gotten away with it this time. It would be sad to have the game delayed, so close to its release and for such a silly reason.