But the problem with this episode is, and that's why I think it's just a coincidence of saving Charlie/seeing Penny, Desmond had a vision of something he had to put together.
Claire is drowning on her own accord, she takes a swim, the lightining strikes on it's own. But this time, Desmond puts together the little Camping trip.. why? He had a vision, but if he never gathered everyone, then there wouldn't have been trouble.
I know he needed everyone, Hurley the wire, Jin for... that scary story (real funny by the way) and Charlie to take the arrow that may have hit Des if he were alone? and all of them to catch the girl as he chopped her down. BUT, it's still odd that it's a flash of something that is totally avoidable.... make any snse?