There is obviously the significantly high risk of it being exposed as fake. And by the way, it wasn’t faked. Talk about a conspiracy that actually matters please.
Discussion
Was the risk of being exposed higher than the risk of mission failure? If you murdered a president in broad daylight in front of dozens of witnesses, you wouldn't think you could fake the moon landing. What was the purpose of the Apollo missions? To put them in on the moon or to win the space race and the Cold War? If it was the latter then faking It would be the smart play.