Sands in Buffalo or Jacksonville. Hoaxes and urban legends aren't synonymous. Someone set out to deceive when he wrote the gas pump needles email. All of which are easily shown to be false. On the other hand, urban legends have multitudes of variations.
People have faulty memories.
They like to tell a good story. Jan Harold Brunvand dubs them. The location is changed from a distant city to the town next door. All to make the story more immediate and interesting. Urban legends are spread by people not seeking to deceive but to warn, amuse, or tell a good story.