Lost!

[Ghoulish Delight]

Originally Posted by JWBear

Who said anything about mystical mumbo-jumbo? I just said that they were not supposed to leave.

Yes, but "not supposed to" isn't enough to explain why the flash didn't cause them to time travel. There has to be a physical difference between them and those that do time travel. Specifically, a physical difference that they both share, and that happened to Locke some time between the time he was on the island before and when he got back (since he USED to travel in time with the flashes). Leaving the island by turning the wheel fits the bill perfectly.