Right right right I do not feel proud of saying this, but on the topic of whether you'd call the police or not...
I may. May. It's hard to say for sure - if the women were crying or looked uncomfortable or forced, I would. If they didn't, I would assume that it was a fetish thing. I'm thinking that this is maybe (maybe maybe) a cultural difference. In England, sex is generally seen as something dirty and uncomfortable, to be ashamed of. I would feel extremely disturbed by it, but it's not necessarily something I'd report, because I would feel uncomfortable about "confronting" my neighbours, even in this direct way, about their sex lives.
I would only hesitate because I know some kinky people worry about being charged with assault for consensual acts, or worry about having their sex lives getting them fired or used against them in child custody cases. I wouldn't want to inadvertently bring that sort of trouble on someone who wasn't actually doing anything wrong.
However, if I didn't feel confident that it was consensual, I'd probably take the risk and call the police. And like I inferred above, if I thought it was a fetish thing, I might suspect they were purposely exposing themselves to unwitting neighbors, which is something I don't have much patience for.
That's the wrong attitude, I know, but it's harder to do these things in reality.
I think that's very common.
Like I said, I grew up around the attitude that if something looks suspicious, you call the police. And I've been in enough situations where I saw that policy work out for the best that it's pretty ingrained in me now.
But even so, there are still times when I'm not sure if something warrants a call to the cops or not, and there have been times when I've wondered, and ultimately decided that no, it didn't sound that serious. And I'm aware that it can be easy to get into a cycle where you keep telling yourself that you'll call "next time it happens."