I’m sorry but with the first drink all bets are off. It is not a “work place” sexual harassment event at all.
You go drinking with the crew then be prepared for things to get out of hand.
I agree with you:
Socializing off the premises is not work-related.
Drinking alcohol is not in the job description.
It takes at least two people to participate in conversations that are personal, off-color and inappropriate. If you have nothing to say and don’t want to listen - LEAVE!
I’m beginning to believe she thought she had a shot at the boss and he turned her down. That would be the humiliation!