http://i50.tinypic.com/70baip.png to see it un-cropped
The columns tell us how many people are left in the game. The rows tell us how many partnerships (as 2-person groups exclusively, for the purposes of this analysis) are still intact.
The "input" used to kickoff the system was "20 players, 10 partnerships."
Based on this, we can see that the bottom-left triangle is impossible to reach, since from (20.10), there's no way to get the number of partnerships to drop that fast. The top-right triangle is also impossible, because, based on the number of players remaining at any point, we can never have less players than 2x the number of intact partnerships.
We can figure out the likelihood of talismans having been given out at a certain point by picking a "Final X players" column and adding together the contents of rows labeled with "1" or "0" partnerships remaining.
Thus, we can see that (ignoring social factors entirely and looking entirely at statistics) at the beginning of the game, there was a 95% talismans would get dealt out by the final five. Conclusion: Brenda, your season was RIDICULOUS. (Not really a conclusion, since we already know that... damn 5%.)
So...
- If Marty leaves tonight, that leaves us 5 pairs in F12.
If we change the "input" to that, we would see there being a 90% chance talismans get handed out by F5. - If Marty survives tonight, that leaves us 4 pairs in F12.
If we change the "input" to that, we would see there being a 94% chance talismans get handed out by F5.
Brook/Jimmy T and Jimmy J/Erica really screwed the pooch on this one, but the odds should still be strongly in our favor to see these immunities come into play.