No spoilers here, but I am speculating about what might happen, so if you don't want to read that, you should pass on this entry.
All of you Lost fans out there know it is a complicated show with an active online community. The producers of the show will frequently throw in little details, inside jokes, non-cannon elements, that only the hardcore—you could say obsessive—fans will pick up on. (No dig intended here; I'm one of those obsessive fans.) It's not necessary to understanding the show, so if you don't pick up on it, it doesn't hurt your understanding of the show one bit. But it's fun if you catch it.
One of these jokes is related to the "red shirts" phenomenon. This joke dates back to the original Star Trek series. The show, infamously, only had one extra costume for actors to wear when the crew went out on planetary expeditions. So, it would be Spock, Dr. McCoy, Captain Kirk, and some random dude in a red shirt. When bad things went down and someone died, guess who it was? The guy in the red shirt.
So, producers of Lost will often put the extra who is going to die in a red shirt. Here's the story of one such unfortunate soul.
In a big finale of a show that is definitely not afraid to kill off major characters, viewers are no doubt wondering whether someone will be killed.
Well, several episodes ago, the character Juliette had a wardrobe change, and she's now wearing a red shirt.
It makes me wonder.