Unlikely, I agree, but not impossible. Hey, it's fun to speculate about it anyway! Especially for tonight's vote when people will only be bothered to vote for their absolute favourites and no-one else. So the unpopular or nondescript celebs could get votes from their families and agents but not much more.
As for what makes it so fake for me - it's been mentioned already in this thread. A few heavily edited clips plus endless linking banter from Ant & Dec and it's meant to be a reality show? We're meant to make up our minds from just seeing a few minutes of footage with no time sequence, no 24 hour coverage, no web viewing? The entire thing is entertaining, but more fantasy than reality.
That said, hats off to all of them, even the ones who are a total nightmare, for sticking it out with all those creepy-crawlies, snakes, humid rain, leeches, bugs, and who knows what else. It's convinced me to stay away from rain forests, jungles and celebrities in future.