Jughead = Flashes Before Your Eyes... and a theory about Walt by LongLiveLocke

I have a theory about what happened with Jughead at the end of Season 5. Remember in "Flashes Before Your Eyes" when Desmond flashed back in time to before he went to the island? At the end of the episode, Desmond thought that he could change things, but when he tried (by warning the bartender to duck), he got clocked in the head with the cricket bat and then woke up naked back on the island in present time. It's as if the universe was preserving the integrity of its timeline by returning Desmond back to where he belonged. Watch that scene again and notice that when this happens, there is a flash of white light that looks just like the flash of light at the end of Season 5.

So my theory is that Jughead didn't go off. The reason they were returned back to 2007 is BECAUSE they tried to change things, and the universe was avoiding a paradox and preserving "whatever happened happened" by returning them back to where they belonged, just like what happened to Desmond. This also therefore goes along with the idea that Jughead was the failsafe that Desmond activated.

The other theory I wanted to share is just some speculation about Walt. It's likely that Walt had the ability to see into the future, as evidenced by the fact that he warned Locke not to open the hatch because bad things would happen (presumably Widmore being able to find his way to the island because of the failsafe) and the fact that he was having dreams of Locke on the beach surrounded by people who wanted to hurt him. So my theory is that the reason the Others wanted Walt was to exploit his ability to see into the future. I think it was so that Jacob could learn what the MIB was going to try to do so that they could subvert his plans. Jacob seemed to have more foreknowledge of the future (like saying outside the Lighthouse that Jack had something important to do). So I think that Jacob actually got this foreknowledge of the future from Walt. And the reason the Others finally let Walt go was simply because they had already learned everything from him that they needed to know.

No real evidence for that last theory. Just makes sense to me.