While the fans waited in a ridiculously large line, members of the press, Blizzard staff, and vendors walked in front of the line, entering the convention centre through a set of double doors. The twist? Only one of the doors was unlocked. As the entrants approached, the front of the crowd would start ooing. If the right door was picked, there were cheers. Otherwise, there were boos.
After watching the game being played, I decided to give it a try myself. I think I did rather well.