Episode 8 (where Alicia is voted out): Prior to the tribal council proceedings, host Jeff explains to the castaways that everybody has a 1 in 9 shot at a million dollars.
Well, this isn't entirely correct. Keith, who won immunity, was safe from being voted out that tribal council. Therefore, at the time, he had a 1 in 8 shot at a million.
No, they didn't have to do anything for ratings, you idiot. Survivor was the highest rated show out of all the networks this entire season. At any rate, the odds are still 1 in 9 because Keith still gets to vote even though he has won immunity. That means 9 votes are still cast. Just because no one can vote for Keith doesn't mean the odds change.
Picky, Picky, Picky. I think this is going a little far. Plus I think it still is a 1 in 9 odds. Just because one person has immunity doesn't mean the odds change.