Last year, I ran a group of friends through "The Lost Mines of Phandelver," because everyone wanted to play and I didn't have time to write an adventure of my own. The players all insisted they had never read or played it before, so I figured it would be a fun way to spend 3-4 gaming sessions.
During the first gaming session, it became clear that one person had read the entire thing. Which is fine, I didn't mind as long as he kept it under his hat and didn't spoil it for anyone else. But this was a guy who enjoys knowing stuff that others don't, and likes to make a big show of it. He warned them of the first ambush, warned everyone about the water trap, coached them on what to ask Agatha and predicted what she would say, that sort of thing.
I asked him about this clairvoyance between each gaming session, and he maintained that he had never read or played this adventure before. I didn't believe him, so I moved a few things around and added a couple of monsters to certain places in Wave Echo Cave.
During the game, after his character spent several minutes searching a certain place for a certain thing and not finding it, he accused me of cheating. Then he got really quiet and pouted for the last two gaming sessions, rarely contributing at all except to mumble his attack rolls. Everyone else at the table sensed the tension, and it really squelched their enthusiasm at the table.
I'm still not sure if I made the right call.