I Genuinely think this is not really a Geek problem. There is statistically large number of people with sexual deviation. For instance, it is estimated that between 3-9% of the population are Pedophiles[1]. At a conference with about 100 people there maybe 3 persons there with a sexual deviation. But it only takes one of those guys to approach all the women in the conference and spoil the whole thing for all of us.
My suggestion is if ever you were to encounter a situation of sexual assault report it immediately to the police[not the conference organizer]. I don't want that guy who hits ladies on the bum to be walking around freely in society. He would not be operating at Conferences alone.
As a side note to how important it's to report these things:"nonincestuous pedophiles who molest boys had committed an average of 282 offenses against 150 victims"[1]. As I said previously, just one deviant can crash the party for a whole lot of people.
[1]http://en.wikipedia.org/wiki/Pedophilia#Prevalence_and_child...