My friend, Ralph, told me this horrifying story that I'm compelled to share.
This summer, Ralph, his wife, and his two daughters went on vacation to Cancun, Mexico. They stayed in a suite in a nice hotel. On their first night there, they settled down into bed, with Ralph and his wife in the bedroom, and the two girls (age 9 and 7) in the sofa-bed in the other room.
In the middle of the night the phone rang. Ralph's wife answered it and a man's voice on the other end intoned, "I have your daughter."
Ralph's wife jumped out of bed, slammed down the phone, and ran into the other room. Only one girl was in the bed. The older girl was missing.
Ralph's wife, not knowing the Mexico's equivalent of 911, ran back to her room and called down to the front desk of the hotel.
"Hello, this is room 416!" she yelled, "My daughter is missing!"
"Yes, that's what I was trying to tell you," the man on the phone said, "Your daughter came down here. She's here at the front desk with us."
Apparently, previously unbeknownst to them, their kid sleepwalks. Awesome.