On episode 9 of series 2, the one entitled 'what Kate did' Kate helps Sawyer out of the 'bunker' after he awekens. He sits on a log and after a second or two he gives a blank stare to something behind kate. When kate turns she sees the horse that appears earlier on in that episode, a black stallion. Now im not sure exactly when it is but i think its during the very first shot of this stallion (outside the bunker and not when it runs kate off the road) there is a hand on the very right hand side of the screen. It only appears for about a second or two, look carefully. It looks like the person who the hand belongs to is wearing some kind of cloack. Anyway this is the first and only slip up i have seen in Lost so far. Happy Hunting for anymore.