12:38am
for the same reason that you buy sausages in packs of 8 and the hotdog rolls in packs of 6.
If that logic made any sense, they would've stopped selling the game after the first four copies were purchased...Why are they selling a 6 pack for left for dead? It's a four player game.
There's no inbuilt limit to how many hot dogs I can eat though (hence my bloated belly). There's a built in participation limit to L4D.