Video taping her may sound good, but I would really think hard and long about doing that to someone. You know that everyone has acted in ways that they would just shudder to see for themselves. I know that unfortunately I have too and if anyone did that to me, I don't really see how anything good could come of it. She's a grown up person and I'm sure she really knows what she's doing but doesn't choose to or doesn't have enough self control, to change. I really feel that you might hurt your girlfrend alot more if you were to humiliate her Mom that way, right or wrong. Just something to think about. Back to concentrating on your own life and how much you care for her. Just my own humble opinion.