I would like it to happen like this: Randy wins individual immunity. Then Bob tells him, "I have a great idea. You give Corinne the individual immunity at tribal council, and I'll give you HIDDEN immunity right now. Then you, Corinne, and I can vote for Crystal, and everyone else will vote for you, but their votes won't count once you play the hidden idol. In the meantime, act like a nutcase for a few days so that the bestowing of immunity on Corinne looks more believable." But secretly, Bob has explained this entire plan and the fake-ness of the idol to the Fang alliance to be on the inside with them (or maybe he doesn't tell anyone, to ensure that there's NO chance that Randy would find out he's being duped). This would make for a grand episode.
Why might this happen?
Bob would do this so that he can get in the good graces of the Fang alliance, and because he wants to see his fake idol royally dupe someone. Also, this is the only way to get rid of Randy if he has won individual immunity.
Randy would do this because he wants Crystal gone, and he fears that Corinne would be voted off otherwise.
Corinne would do this because she gets individual immunity. Also, remember her quote from the preview: "We have to get this right. If we get this right, the whole game will change."
The remaining five would do this because it is the only way to get rid of Randy.
Jeff Probst would do this because it would make for one of the best episodes of the season--someone with individual immunity going home. No hype. Just truth.
Why won't this happen?
Besides being too good to be true, it doesn't account for the fact that Randy and Corinne are trying to convince Matty to vote against Crystal or Kenny. Of course, that could have happened before Randy wins individual immunity.
Bob doesn't seem that proactive.