my friends dragged me into the bathroom and turned off the lights and did that when I was a kid because they wanted to see bloody marry,
they also insisted we "miss" the buss home one night so we could look for the little ghost boy that was from one of my stories,
i liked telling ghost stories when I was a kid,
I remember hearing that a lot - most often in elementary school. Although I do believe there is validity to the statement so I never would try it. Also, I believe there is more to this than only saying her name three times. Words have a powerful significance - and some words shouldn't be messed with.