James, I've had my planes judged numerous times...on the flight line, in the pits and under my canopy. I've never had a judge pick up my plane nor look under it. I haven't seen the actual appearance judging at the NATS, but I believe they look under them and pick them up. Sparky can clarify this point. I have received several appearance trophies and never detailed the bottoms as I have the tops. "Go figure."
Norm