TRUE (mostly): If you decide to wake sleepwalker, you are literally risking your life. According to Ken Jenning (in his book Because I Said So!) 20 people have been murdered because of "sleep drunkenness" — a condition similar to sleepwalking. He also cites other studies that link waking up sleepwalkers with violent resistance. That being said, it's likely you won't be murdered while waking a sleepwalker. Just be sure to duck.