Sleeping Issues

We have a wandering sleeper in our house. I'm not mentioning any names, but she starts in her bed and ALWAYS ends up somewhere else...the couch, the chair in my room, James bed, my bed, William's bed, the floor, etc. Thankfully the boys are heavy sleepers so they hardly notice. William suggested after a night with the accused that he was going to give her a "verbal" for her behavior. I decided not to ask how he learned about "verbals" at school!