This is so fucked on so many levels.
Reading the comments here, have brought up one of the major issues I've always had with the technical community -- its inability to empathize.
And worse, when it comes to sexual harassment and assault, it's almost as if there's a disincentive to empathize with the victim, resulting in straight-up, outlandish comments that are on par with those of extreme, right-wing talk radio hosts.
The line about what is or isn't normal things that Americans do at conferences is just bullshit. You put 500 people with a shared interest in the same room, you'd be surprised at what quickly becomes "normal" or justified. It's actually called herd mentality.
At this age and point in your life, with all the media coverage and information surrounding you about sexual assault, and to use your Girls Gone Wild example: the girls who have claimed, and successfully proven in a court of law that they were exploited by GGW; how can you use the excuse that he didn't know he crossed a line?
Has he been participating in a self-imposed media blackout for the last 10 years? Has he never thought of the day he might have to discuss the issue of sexual predators with his three daughters, and how they potentially come in all shapes and sizes?
And to top it off, you're shocked that she said the touching was common behavior for coworkers. What does that tell you?
That she was really trusting and naive, or there's a culture of predatory behavior in her workplace, or BOTH.
As a manager, you yourself have an obligation to not make unwanted advances across the personal boundaries of your subordinates, and ensure to the best of your ability, that your subordinates are also safe from unwanted advances within the company. There is absolutely no question about that.
In fact, if you do indeed choose to start a relationship with a subordinate, you absolutely need an a CLEAR line of communication that establishes that, yes, your subordinate does indeed want to engage in relations with you, and understands it has no bearing in your career/position or their career/position.
This even extrapolates to hooking up casually -- you need a clear signal that both parties are okay with this. Sometimes, it's reciprocated, non-verbal communication, and yes, other times it can be a BLUNT question that is purposely meant to remove any ambiguity from the situation, and end in one of two clear results: yes or no.
You cannot assert that no man has ever asked first. You can only assert that you've never asked first.
And then you've flip-flopped on your own logic regarding vilification.
You give him the benefit of a doubt of making a mistake influenced by alcohol, that "is stupid, juvenile behavior on his part, which he would not have done sober."
But later you reverse your position regarding her DUI, and insinuate that this may not be her first time, and she may have even developed a habit of driving under the influence.
What if this isn't Joe O'Brien's first time? What if he developed a habit of it? What if that's the reason he's checked himself into a 6-week mental health program as you stated in other comments? Do you check yourself into a mental health facility, after a single "juvenile" mistake?
EDIT: What if this occurred with such frequency, that he did indeed have an "agreement" in place with his wife, as he so creepily stated?