The OP doesn't specify, but her alleged harasser is well known in the community already. So I would assume he's not just a regular conference attendee; he's pro

The OP doesn't specify, but her alleged harasser is well known in the community already. So I would assume he's not just a regular conference attendee; he's probably got some technical reputation, and may be a featured speaker. That's usually what makes these things extra extra difficult. As for whether the bar is really part of the conference, I agree it's a bit of a grey zone. But in every such gathering, the unofficial parts are where most of the important stuff happens. If you have a conference where the women feel unwelcome doing that stuff, you don't really have a woman-friendly conference.