Assuming that my former teenage fantasy/legal colleague is right, she perhaps stayed silent for way too long?
It's hard for me to say who is wrong and who is right here. I don't doubt for a minute that Fowley, given half the chance, would have molested one of the girls under his patronage, but whether Cherie, Sandy (never one to take much interest in hetero-sex) and Joan (ditto) sat there and watched, who knows? Subjectively, Jackie might have indeed seen something, but she was drugged out of her mind and barely conscious. Not remembering much of the rape (which I don't doubt happening) and having a vivid recollection of who was actually in the room doesn't necessarily go too well together.
Doesn't excuse Fowley or any other bystander who just watched.