What happens when they all find out about Michael's betrayal? They haven't really faced this situation before. I've always wondered what kind of justice they would mete out on the island, assuming they get the chance. It seems to me that, plotwise, Michael can't be allowed to get away with it. The writers could always take the route they do in so many Disney movies, with the villain (and yes, Michael is a villain now, isn't he?) simply falling to his death so that no one is actually responsible for his death.
I don't hate Michael. My reaction to him has always ranged from mild indifference to boredom to intense dislike. I did kind of hate him when he blamed Sawyer for Walt's kidnapping and refused to acknowledge Sawyer a) getting shot trying to save Walt, b) Sawyer saving Michael's life and c) his own bad parenting. But that's how I judge everyone: Are they mistreating Sawyer? If so, grrr! Of course that's not real world ethics or even ideal Craphole Island ethics.
But given what Michael has done, I don't see how he can live. Assuming he doesn't die in the finale (and I've heard nothing to indicate that he will), how will they treat him once they know? Mere shunning won't do it this time. There would have to be an island death penalty. He could strike out on his own, like Danielle. But the way I see it, the only way this can end is with Michael's death. I've wished more fervently for other characters' deaths (mostly for the crimes of being boring or very bad actors), but his seems inevitable.
Here's a list of how they've handled justice on the island previously. Aside from some shunning, no one's had to answer for any of their misdeeds.
1. Crime: Boone steals the water
Outcome: The makings of an ugly mob scene until Jack arrives in the nick of time and delivers his "stick together" speech. Boone is snubbed for a while, as Sawyer points out he's now "at the top of the most hated list."
2. Crime: Sawyer withholds Shannon's asthma medicine
Outcome: After talking to him doesn't work, Jack tells Sayid to go ahead and torture him. When it comes out that Sawyer is innocent, Kate is sympathetic, but everyone still considers Sawyer the island pariah.
3. Crime: Sayid stabs Sawyer
Outcome: Sayid exiles himself temporarily. No one ever calls him on what he did and eventually Sawyer forgives him.
4. Crime: Locke knocks Sayid out and ruins the transceiver
Outcome: Sayid is upset when he finds out much later, but chooses to do nothing
5. Crime: Charlie shoots Ethan, killing him before he can tell them anything
Outcome: People's opinions of Charlie dip a little lower
6. Crime: Locke deliberately leads Boone to his death
Outcome: Shannon and Jack both blame Locke. After Sayid won't kill Locke for her, Shannon tries to shoot Locke herself but misses. Jack is visibly disappointed, LOL. Jack never fully forgives Locke, but they mostly put aside their differences on a day to day basis
7. Crime: Jin is blamed for the boat being torched
Outcome: Sawyer tracks him down and brings him back to face Michael. Jack wants to stop Michael from beating Jin up, but Sawyer and Sayid hold him back and everyone just watches as Michael beats Jin. When Jin is revealed to be innocent, he and Michael team up to build a new boat and become unlikely friends.
8. Danielle steals Aaron. Later, Charlie steals Aaron
Both are shunned and shamed. Locke beats up Charlie.
9. Crime: Ana accidentally shoots and kills Shannon, then freaks out and takes Sayid hostage, after also deciding to leave Sawyer to die
Outcome: The other Tailies turn against Ana, leaving her alone with Sayid. He declines to shoot her. When she comes back to camp, she is quickly welcomed as one of them and becomes a trusted leader/soldier. The only ones who keep their distance are Sayid, who is still in mourning, and Kate, her rival for Jack, and Sawyer, who understandably doesn't like her for her continued abuse. Sayid ends up teaming up with her(!) to find The Others, and tells her he blames them, not her. Sawyer also doesn't hold a grudge for long either.
10. Crime: Michael K.O.s Locke and steals the guns to go look for Walt
Outcome: No one blames him and they rush to bring him back
10. Crime: Henry Gale is thought to be one of The Others
Outcome: He is tortured until he admits the truth
And I've left out Kate manipulating Jack to get the suitcase (outcome: some yelling, some disappointed looks, temporary shunning), and Sawyer stealing the guns (same outcome, really) and countless other stuff, probably.
So all these "crimes" have been overlooked or forgiven or forgotten. But what Michael did, once revealed, cannot be forgiven. Regardless of how you feel about Ana and Libby -- I want to applaud him, myself -- cold-blooded murder can't be shrugged off.
Whether you like Michael or not (and he's actually finally gotten interesting to me now that he's gone over to the dark side), is there any way he can live freely among them after this gets out? I just don't see how. I know that forgiveness and spirituality are huge on the show, but in this case?