Okay, so, this is probably going to be a really unpopular comment for me. But I'll admit, I've read modules in the past when I was a player. But my reason for this is that our DM is my husband, and he gets frustrated very easily when the party doesn't understand a puzzle, goes off the rails, or makes bad decisions. We have a few players that will go so far into left field that it can be very stressful for the DM. I know this because when my husband isn't DMing, I am.

So after a particularly bad night of gaming where the party was making a lot of unwittingly bad decisions and making the DM close to the point of rage-quiting, I decided I would read the module to learn the proper choices, backstory, etc. The next time we played, I didn't make any final decisions for the group, but instead I threw out ideas, concepts, and suspicions to the rest of the party in order to steer them the right way through the game. I ever once said, "This is the answer". I was never meta about anything I said -- I always tried to ask the right questions, or find reasons why my character would say or do a certain thing. I didn't steer the players away from traps, side missions, or NPCs. But I would plant the seed in other player's minds to help them think along the lines of how the module wanted to you handle things.

After learning the module and steering the party appropriately, the DM (my husband) and the party had a great time. My husband was really happy with our decisions and talks really highly of how well we did. I read the module so I could keep the party on track and make sure everyone had fun, I didn't do it so I could spoil the fun for anyone -- quite the opposite.

I've been gaming for 18 years and I've done this on a few occasions and it's always worked out well for the group. I wish it didn't spoil things for me, but I'd rather spoil my fun a bit, rather than see the party crash and burn, and the DM flip the table.