LOL
Sleepwalking runs in my husband's side of the family. My father-in-law does it, my husband does it, and now my 2-year-old does. It's a strange thing. They have their eyes open and can navigate hallways or doors just fine, but they aren't in the same reality as the rest of us. My mother-in-law tells a story of being woken up in the middle of the night by her husband yelling at an "intruder". He was sitting upright in bed yelling at a dark corner. Then he collapsed into a deep sleep, leaving my poor mother-in-law half panicked and worried that maybe someone was in the house.
I was particuarly amused at my husband when I woke up to find him "folding clothes". He had his eyes open, and was going through the proper motions, but he was obviously asleep; he didn't react if clothes fell out of his hands before he was done "folding" them, tried to fold everything as he would a towel, and often picked up an item to "fold" it again.
Stairs are a little scary. My 2-year old will sometimes fall back into a deep sleep *while* sleepwalking, meaning that he falls flat on his face. This doesn't seem to bother him.
In my experience, it's just fine to wake a sleepwalker. They are usually *very* disoriented, however. I usually call them by name and tell them, "You're asleep. Go back to bed." over and over until they finally register what I'm saying. My oldest used to sleepwalk when he was little, and his particular oddity was that he would actually try to hold a conversation with you. It wasn't very coherent, though. I could say, "Donovan, what's your name?" and he'd say, "I don't know!" It would take a while to get the right answer, but once I did, I knew he was awake. Well, at least awake enough to go to sleep...LOL.