Hello there!
My name is Lucy - I'm a newbie to this forum I just saw this episode in New Zealand where I live last night, so don't know what happens in the rest of the season (please don't tell me!)

But I have noticed the 'others' tend to have some fascination with kids...do you think they are keeping Walt in the place Claire was kept? I mean they've probably moved on as it was abandoned but do you think he's in a similar arrangement? They also took the boy and the girl from the tail end of the plane and of course Rousseau's Alex.

Maybe they take kids so they can raise them as their own? My other theory is that the whole programme is a grand scale human experiment and they take the kids to keep them save and make sure they have medical attention etc?

Who knows.