User blog comment:Arbington/DLC Theories/@comment-1691295-20100913114012

Just remembered something. In the source I posted for the Vehicle section info i posted to the Mass Effect 3 page, Casey Hudson talks about DLC quite a bit, and says that eventually with the DLC they'll be assuming everyone has finished the game. You can see the progression already. So it's very possible the next piece of DLC may assume everyone has beaten the game (it will likely have been almost a whole year since the game came out), and maybe (hopefully) will be exclusively post-Suicide Mission.
 * Zaeed knew, to a certain extent, that people hadn't finished it yet (it was there day 1).
 * Kasumi assumed people hadn't finished it yet.
 * Overlord assumed some people had, and some people hadn't, beaten it, so was completely agnostic to whether or not they did.
 * Lair of the Shadow Broker assumed most people had beaten it, and included substantial bits of dialogue referencing the fact.