Definitely not an urban myth. I was a secretary for a bunch of engineers, and one of the installation team guys (big gov't contract, lots of workstations and laptops) called in frustration because a client's laptop kept beeping and then dying. I was supposed to take complete messages and hand them back, so as I was writing the problem down I blurted out "is it plugged in?" and was rewarded by "OH SHIT!... *mumbled*thanks."

*snerk*