Well, I think I said it before, but silly me - I only bought in because of the free swaps. I have a handful of other portable chargers already, and did not "need" this solution, but bought in for the convenience. I would like to think there are others in the same position, that like me, will now say "nevermind."
I do agree with you there is a certain component of guests that use it exactly as you say...they will still buy. Although I think it's likely the "OH S#!t crowd" is buying a rod and not just swapping because they probably forgot the last one they bought at home too.
That is exactly why I bought two of them. I am a local, I am an annual passholder. We have two "go bags" for when we go to any of the parks. They consist of sunscreen, refillable water bottles, umbrellas/panchos AND Fuel Rods. We don't have to worry about phones going dead. The Fuel Rod out of juice? Just swap it.