My goodness, my 6yo dd just got up from bed, came in the sitting room, pulled down her pants, sat on a chair and peed, then pulled then up again and went back to bed and back to sleep...we just gaped and didn't know what to do - I think I remember being told once that you shouldn't wake up sleepwalkers...I assume she is sleepwalking, my dh sleepwalked and did things like this when he was little (so my in-laws tell me). It went away when he was 8 or 9.
She has never done anything like this before.
Please please tell me this has happened to somebody else...it is sort of funny, but a bit freaky...just sort of glad we don't have carpets in the sitting room.