The message to the audience is this: don't like the ending? You get to invent a different one! And that's ridiculous. Giving away something to someone in an audience vote? Oh, maybe. But a million dollars? The same prize you actually get for winning? Come on.
In any event, the castaways all know instantly that the money going to Rupert is a foregone conclusion, and so do I, and so do you. Because that's why they're doing it in the first place. Because this is a manipulated, fixed ending, forced by the producers. And as much as I generally hate the expression about shark-jumping and find it an overused cliché, I have never seen it more apt than here, because this is the moment where the entire show changed from a mischievously nasty show that demanded that you the viewer risk an ending you didn't like to a pathetic display in which you may expect to be pleased by the outcome, and if the majority doesn't get an outcome that pleases it, then it may expect to be given that outcome as an afterthought. Because who really cares about the competition, right?