Alright this is why the ending to The Ring makes sense.
The reason that you don't die if you make a copy is because, as the boy said, she never sleeps, meaning that she keeps on killing and killing. The problem is, is that if a copy isn't made, there is chance that the original will be lost forever and she wont be able to kill anymore. By sparing the life of the one who makes the copy, it's sort of like a 'thank you' from the little killer girl...it allows her to keep on killing.
Now yes i know this could potentialy backfire on her because if everyone made a copy then no one would die, but most people are dead before they realize it...or think it's just some prank and don't think about it until just before they die.
Six Million Ways to Die, Choose One