In yesterday's Metro: the menace of killer fans. No not the creepy stalker kind, but electric fans. It's a phenomenon found only in South Korea, where they believe that if you leave a fan on overnight, it can kill you. Method: unknown. There's even a website devoted to it.
I think it's urban myth gone rampant. It's probably a subconscious expression of the anxiety caused by living so close to Kim Jong Il's regime, with his missile tests. Like anyone in an anxious state, the brain tries to rationalise the anxious feelings, and latches onto the first thing it can think of, which, at the moment, is killer fans. Trying to reassure the Koreans won't do much good, as their anxious minds will simply latch onto another source of fear. And if that turns out to be something more logical, such as weapons of mass destruction, it could lead to trouble.