Bungie has definitely confirmed that competitive gameplay will definitely be a major element of the game. We currently don't know how it will work entirely, but I can imagine some implementations for how to do it. PvP would not be restricted to certain areas, but rather, it would be a gameplay option. I can cooperatively go on a raid and ensure that the only people shooting at me are the enemy AI, or I can choose to do the same raid competitively, and there is no guarantee that the players that I meet won't want to kill me. With the added risk, comes added rewards, which would make this mode appealing to anyone who has confidence in their skills I just see no reason to restrict the PvP to certain areas when all you have to do is turn off friendly fire and you've got yourself a firefight :) From what I understand Campaign is Multiplayer. There is no point in the world where you can't encounter other characters (probably), you might be pursuing some Cabal as part of a Campaign Mission, and see some players chilling out on some rocks as you speed past on a Pike. Does that sorta make sense?