I know that there's already a ton of evidence that the 2003 leak did indeed happen. Valve themselves have stated it happened and many, m a n y models, textures, sounds, and maps back this up...
But imagine that somehow every single bit of it was fake? Someone trying to pull off an extremely elaborate scheme to make a fake leak seem like a real leak, and succeeding? Only to reveal it was all a huge lie? What would happen, and how would the majority of the beta community react to the news?