I snapped a couple of screen shots of the Orbital Drop Shock Troopers that I have been encountering while playing Halo 3's campaign. These guys, were not fighting along side me, when the game launched.

My friend Reetesh said, "maybe its some kind of secret marketing technique where they are trying to make people feel that the ODST were really a huge part, hence a game around them, making sense." I think he may be onto something.