I think the whole banning of all newer users is a great idea going into the last stretch of LOST. I think many simply create back-up accounts in case they're banned for spoilers. And I do not want to spoil myself (although I do watch the 30 second sneek peeks, as they don't really give away anything IMO) this far into the series. I made the mistake of that by reading spoilers all the way up to Sundown. I want the finale to catch me completely off guard.
Good idea LP
Now for theories. I'm gonna jump on death bandwagons. Frank = dead. They made a point of Jack taking the last air tank, and needing an air tank to make it to the surface. Sorry Frank, you were doing so well with your one-liners.
Also other death thoughts (grim, I know)
Ben = dead by series end (most likely towards very end of finale)in some magnificantly acted, drawn out, stressful-to-watch event that tottaly redeems him and provides a massive boost for "good" whatever "good" may mean in the show.
Also, I beleive we will see MUCH more of our beloved characters snuff it. I think there will be about 4 OT characters left by the end. (still not sure how FST will contribute)
And idea: Locke says he's going to finish what he started. It was made very clear that he can't kill them. He could get someone else, but I have another thought. What if he DOES kill one of them, but in doing so, he himself becomes weakend or mortal due to breaking a rule of sorts