This may be Obvious by Locke4God

Short this time,

The way Flocke was insistent on getting all of the remaining candidates together really made me curious. Why would all of the candidates help him leave? Can all of them collectively pierce the barrier? Can they all together magically start the plane?

Then it hit me. He wants them all together so he can kill them at the same time! That's right isn't it? I think. Hummm.

Remember Richard was sure that MIB wanted to kill everybody, and we know that MIB has said that he'll kill any candidate that takes Jacob's place, soooooo

If he killed them one at a time, he wouldn't have anybody left to kill the last person, who would theoretically become the new Jacob. But if he got them all in one place, he could have them killed all at once in a large firey plane explosion, or crash, or whatever.

2 notes from there. Perhaps if and when the candidates & Jacob are all killed, the snowglobe falls apart and the island just becomes a normal island in the real world that anybody could get to or from. Also maybe that's why Jacob's spirit is still hanging around. His replacement wouldn't be much of a new Jacob if he/she had no idea what was going on. It might make sense that Jacob's spirit would alway lingers until it's able to absorb itself into the new candidate.

I just had a third idea. Peraps MIB has been a ghost all along, both the Titus & Flocke versions. More people than Hurley have seen ghosts. So he's like a spirit and that's how the newly dead Jacob could possess you and why MIB says he has no body.

Lastly did anybody feel that Jack's "do you trust me" conversation with Sun on the beach was suspicious? I mean the ending where he asked her to go to the plane with him, and then promised to reunite her with Jin and take her off the island. Then he extended his hand. WOW, that just seemed exactly like what Flocke was doing.