Honesty, there are a lot of reasons people probably ask in advance. New to cruising, new to a ship, like to have plans, builds anticipation, etc.
For us there are two things. First it is build up, simple anticipation. Like an appetizer. It's not planning out every minute, but having an overall sense of what they do on sea days, what movies were showing at the Aqua Theater, etc. I realize that for people who cruise several times a year this seems silly, and admit that once you have been on a ship a number of times (even 2) it is less necessary, but to me it's like watching a movie you enjoy, even though you have seen it 10 times. I also look at the CD list and see what ship my CD is currently on. It seems like the activities change more by CD than ship. I will literally decide to go to Love and Marriage and Quest based more on CD than anything else. Recent compasses also give an indication of the Trivia Topics.
The bigger reason, which is probably the point for a lot of people, I am a type A personality. I could no more not research and plan, than I could not breathe. Where others are asking "Why do this", I look at it as why not. How am I hurt by doing it? I am happiest when I am gathering up data. I am never disappointed, because I know what might happen and am prepared.
I do admit that I use Google and the Search Function here and don't think I have ever asked for one. Also I focus more on Youtube videos, deck plans, port information, and recent reviews. But I do pull compasses as well.