Sexual Harassment is a problem, but I am not convinced that a card system is the way to solve it. If a woman is being a jerk at a conference does that mean I can card her? I was just reading of a top official (a women)in the US government who is accused of sexual harassment of her subordinates. Any sort of rules that favor one sex over another will be used to do just that. I am a big fan of codes of conduct at conferences. If someone violates them (be male or female) they are tossed out, period.