It's true. Go to the part of the tutorial where you need the horse to jump over the water and f8 through the crack in the water, left side.
So I was messing around with the mission editor on the slopes and for some reason I found the Tut house. So I lightened the mission again and went inside. I started out in the beginning, Looking, moving, jumping, ducking, building, jetting but then I got to the light room and my light wouldn't work in the room. So I f8ed out of the room and accidentally skipped a couple rooms and got into the new "Ride" room. I noticed their was no water and when I walked across the empty water pit I noticed a crack in the wall and I realized the "Secrets" room.