Oh goodness. I wish you'd thought to print up that snopes page and make her sign a copy of it, then take that copy with her. It sucks that people are still taken in by this. What's even more galling is that she had retconned history and completely blanked out the part where you had implicitly warned her NOT to do this. These kinds of things totally make me understand why my 4th grade teacher would occasionally beat her head against a wall, with the saying, "You can lead a horse to water, but you can't make him drink!"