The Trek game's plot is basically a mystery at this point. The large duranium chest that Captain Sulok asked them to deliver has mysteriously vanished off of their shuttle in DS9's landing bay, and the players are actively searching for it.
In the last session, one of them asked a question that would reveal everything. We're still so close to the beginning of the story, that I really didn't want that much revealed yet, but I always figure that the players should be rewarded for their ingenuity, and not penalized for the sake of the story. So I answered honestly.
The thing is, I know what's really happening, and they don't. So what seemed like a completely obvious situation that would give everything away, just sailed over their head with nary a notice.
The thing I really like about this, is that later on, when the reveal actually happens, they'll be able to look back at this session and say "Yeah... the clues were there all along!" I think that kind of story consistency really enhances game play.