I will go out on my limb here. It was a mistake on his part. See if you are willing to let him go with a caution. I know everyone is crying for blood and it is justified. Going to HR will likely ruin his resume for life (possibly).
I think this perspective is at least worth discussing.
On the other hand,
a) He's in his 30's and should know better.
b) He has no rapport with OP and knows basically nothing about her.
c) This is a pattern of behavior that women in the industry have to deal with all the time, not just an isolated incident. (See the comments in the thread.)
When I look at issues like this as a guy, I have to remind myself that "feeling sorry for the perpetrator" is in fact one of the many anti-patterns that leads to this kind of hostile environment in the first place. So I cannot judge the victim for whatever decision she makes.
Were I in her shoes, I would probably send the guy a harshly-worded e-mail instead of escalating to HR. I don't like the idea of someone losing their job over a really dumb decision they made in the heat of the moment. But I am not a woman and I haven't had to go through life getting worn down by dozens of incidents like this one, so my perspective here is kind of meaningless.
No. Just no. I don't think one mistake like this should ruin someones career but it's pretty impossible for this to be a mistake. He even admits in his email that he shouldn't be doing this. If you are senior enough to interview to be interviewing people you should know how unacceptable it is to engage in that kind of sophomoric bullshit.
It's really nice to give this guy the benefit of the doubt. Maybe the girl was just so perfect he could't help himself and it was a one time thing. I don't know but honestly you really need to consider the converse. What if this isn't a one time thing. What if this is the way he acts whenever he interviews a woman. This absolutely needs to go to the proper persons (eg HR, CEO/CTO since they might not have hr) who can handle the situation.
I tend to agree with you. My viewpoint is I am assuming this is a one time thing and there was/is no precedence. But this can only be confirmed by talking to HR. So yes, she needs to talk to HR.
HR exists for addressing problems like this. You absolutely should talk to them. I don't think it will "ruin his life" but whatever action is taken (if any) is ultimately up to his bosses. This is unacceptable behavior and if no one ever says anything about it, there's no reason to think it won't continue.
> Letting HR know about the incident will likely cause this person to be terminated.
HR doesn't generally have the ability to decide to fire people. So if this person's bosses, in consultation with HR, think this is worth terminating someone over, that's certainly their right.
I don't want to parse words with you, but this is wildly inappropriate behavior and it certainly should not be ignored. HR is the correct department to make sure it gets addressed.
And, frankly, some companies may believe that "creepy" and "mean" behavior on its own is a serious offense even if, as you assert, no abuse or harassment occurred.
After some thought, I agree HR should be involved to caution him. As for ruining his life, it feels like a stretch - but imagine, he is publicly outed (with this much attention, it's possible). People have their pitchforks out - so I know this viewpoint will be downvoted. But it is best if she brings this issue with HR and deal with it internally with the company.
Just because people disagree still doesn't mean it's harassment.
Also, nearly this entire post's comments are debate. There are people on both sides. This issue is not black and white, anything but. If you read some other comments, you will see it's not so "overwhelming." A majority, yes. Overwhelming, no.
When you admit, in the act of typing out an email, that you're doing a bad thing which you should not be doing, and then you go ahead and hit 'send' on that email anyways, it becomes more than just a 'mistake' and turns into 'willful malicious action'.