Rumor: Halo 3: ODST Trailer Confirms Halo: Reach is a Prequel

11 days ago at the Electronic Entertainment Expo 2009, Bungie Studios showed off their most recent product; Halo 3: ODST and announced Halo: Reach. Since then many h gamers have been analyzing the Halo: Reach teaser trailer and many have found certain clues that hint that the game will be a prequel to other games in the series. Some of those clues are things like the fact that some beleive it will follow the storyline of a novel based in the "Halo" universe titled "Halo: Fall of Reach". Some other people have speculated that it is a prequel due to the fact that an unidentified voice says "Spartans on the ground" notice that the mysterious figure said "Spartans" in a plural sense. Why does it matter that she was referring to multiple Spartans? Well becuase at the beggining of "Halo: Combat Evolved" Master Cheif was the last known living Spartan. Those things are not what I am here to talk about though. I am here to talk about a new theory of why Halo: Reach will be a prequel, thats reason is becuase if you watch the E3 stage demo of Halo 3: ODST(viewable here http://www.youtube.com/watch?v=oSrOkk7jRbk&NR=1 ) than you can see about 35 seconds in it says "Remember Reach" written on a wall.
Since Halo 3: ODST takes place before Halo 3 and it is very hard or impossible last I checked to remember something thats hasn't happened yet.