Masaki:

You are 100% correct...BUT, I would guess that the show producers thought that the fear of flying would have pushed at least a couple of players to the bikes.

I've done para-gliding (where the motor boat pulls your parachute up). Andi has actually jumped out of a plane (with a parachute I rush to add!). While I have a real problem with ever doing that, I scuba dive. Andi has a real problem with that.
So, I guess they were hoping for a split via phobia lines.

Doug