Despite Rockstar pleading to the public to not leak their game, even they didn't doubt that the game would probably get leaked and torrented before release. And the result of leaked copies of the game selling before the release is filled with clips and footage of the game all over the internet on websites like Youtube, Facebook, Reddit and Instagram.
Rockstar are trying their hardest to remove the footage, but because there are so many different people uploading footage, it's going to be pretty difficult.
It's become a trend to see popular games leak before their release date. For example, people were playing Halo 4 on the Xbox 360 at least a week before it actually came out. Microsoft responded to this harshly by banning any accounts that showed online play history of the game before the release date.
Rockstar doesn't have the manpower or backing by either Microsoft or Sony to do this so it's likely leaks will lead up to the game's release. The cause of this is mainly due to game retailer employees selling off copies before the release date, and once millions of copies have been sent out, there really isn't much you can do to stop it.