She was an RM and was about 57 years old (never married) and she told us it had happened at her Sacrament meeting the day before.  There was absolutely no basis for her to make up the story.  It was totally off the wall that she was even telling us a story like this, but while I was not in the meeting, I don't believe she heard some Mormon urban legend and decided she'd come to work and tell all the rest of us that it had happened in her ward.  She had used names and all.  It seemed obvious that she was telling the truth, but no, I didn't witness this for myself.  This was about 2005-6, so this could have spurned the stories you subsequently heard.  I'm sure that if it did happen as she told it to us, that the story traveled far and wide from all the others present.  She had appeared totally serious and having worked with her at that point for about 5 years, I never doubted the story.  I thought it was about the funniest fast & testamony story I had ever heard.