I think you are onto something.Plus that water looks so clear I can't believe they couldn't see it right away. I too thought they should have kept the old campsite and made the losers go to the new one. Why waste all that energy building a new shelter?
Here's a thought too - maybe the "wave" was from Jeff's speedboat.
They were inside the reef..the water was very calm..no way you can have a wave big enough inside the reef.. to toss an outrigger..