You have to wear a hard hat to go to the toilets, which are right next to the truck scales. On the other side of the wall, there are people in claw loading cranes, literally tossing cars thru the air. Its part of the fun. Sure we speculate, but the possibilities are near endless. We did suspect that our first challenge would involve water in some way, as they had Geo renew his diving certification, but not anything further.
Teams really do find out, on camera, the morning of the build.
RDF finds the experts, and assigns them to the teams. Each expert knows in advance what the challenge is to be, and has submitted suggested designs, with a critical parts shopping list. The team meets their assigned expert the night before the build in the hotel bar, and a running joke is that you can't ask what they do for a living. All we found out the night before about our last expert was that he was an amateur league cricket player. Yes, but not with very much.