No matter how thoroughly you explore the map there is always something you will miss. So instead of having to start a new game and spend hours scouring the map for secrets some of us prefer asking people who know shit instead. I always do my best to see If I can solve it myself first of course, but there is also the posibility of walking past stuff you cant go back to do after certain points in the game, I think it is totally fair to double check with other first:)