A Brooklyn Sex Club Promised Freedom. Some Called It Rape.

The townhouse in Bushwick, Brooklyn, was once a beacon for Jennifer Fisher, a place where she did not have to hide that she was polyamorous and kinky, because her housemates were too.

The landlord, a group called Hacienda, had a unique vision: creating a community of sexually adventurous people whose house rules preached consent above all else, particularly during the orgies they threw in the basement every week. Over the years that followed, Hacienda flourished, and sex positivity, a movement to destigmatize different types of sexual expression, became more mainstream. Ms. Fisher felt a measure of pride at being part of a community that had pushed for greater acceptance of her lifestyle.

That feeling helped her ignore what she described as Hacienda’s dark side: a series of claims from guests and tenants who said they were victims of sexual or physical assault under its auspices.

Then, she said, it happened to her. Ms. Fisher was in her kitchen at Hacienda in spring 2012 when she was approached and badgered into sex by a guest of the sex party she had left downstairs, she said. She awoke feeling that she had not given her consent to what had occurred — that she had been raped. Yet a fear of betraying her community, the circumstances of the encounter and its very setting stopped her from reporting it to the authorities, she said. It was a decision she deeply regrets.

“How do you call the police to report something that happened at a sex party?” Ms. Fisher said. “They’d come and say, ‘OK, which deviant do I arrest first?’”

At a time when non-monogamy has become a drop-down option on dating apps, groups like Hacienda have risen to new prominence, drawing in curious newcomers and profiting in the process. Participants envision these groups as a place to push the boundaries of sexual norms — or flout them altogether — in the safe company of like-minded people. But Ms. Fisher’s story and others like it reveal the inherent tension between the desire to create a freewheeling space and questions of consent when one person’s kink can be another’s crossed line.