When someone in your social group is hitting on you or pestering you.
A thread the other day linked to a page where women were asking advice about some man in their group of friends who was hitting on women. Men--as well as other women--often didn't see the problem or want to hear about it.
In a social group I belong to, a woman was pestering me. It wasn't sexual, she was just annoying, invading my personal space and acting rude. I was told she'd done this before, that she liked to "needle" people and she'd pick a certain person, then move on to someone else.
After I forcefully told her to back the fuck off, she stopped bugging me.
My point is, in my experience--same as the women in the advice column--other people, most of the time, didn't want to acknowledge the problem. They didn't want to hear me talk about it, either. And since it wasn't THEM who was being annoyed, it was easy for them to ignore.
I submit it's the same with women being harassed by a man in their group.
(Wish I could link to the thread I refer to, but I can't find it. If someone else can, TIA.)