That's true, they did. Several people have spoken to Greg Nations, script coordinator for Lost about this. His answer: ABC really screwed them over. They have limited control over the marketing for the show, so if ABC builds it up too much, there is nothing they can do about it. Basically, they never seem the promos until they actually go on air.It stinks for us fans, but it stinks more for the production team.
see that discussion here:
ABC Promotional Department - The Fuselage