Hmm...it is true that all the times we have seen him sleep-floating, he has been under stress. (Although he wasn't having a nightmare in Just Say Noah, the whole situation was an extraordinarily stressful one for him. Although he and Lois have reached a bit of a detente right before he falls asleep (in one of my favourite scenes of the entire series), his body and mind must still have to deal with the stress that had accrued over the course of the day.
I don't recall - have we ever seen him sleeping at a time when he was *not* under stress?
Dcarson's point about him floating in an emotional situation while awake at the White Orchard ball does give some more weight to the idea. I hadn't thought about that; to be honest, I had always considered that floating, aside from being a nice bit of humour, to be a G-rated depiction of a non-G-rated biological response of Clark's to seeing Lois all decked out.
cheers,
Lynn
