The article explains that she most likely had her privacy settings well enough to protect herself.
Mr. Acosta had chosen open. "I was so gung-ho about the chorus being unashamedly loud and proud," he says.
But there was a trade-off he says he didn't know about. When he added Ms. Duncan, which didn't require her prior online consent, Facebook posted a note to her all friends, including her father, telling them that she had joined the Queer Chorus.
When Mr. Acosta pushed the button, Facebook allowed him to override the intent of the individual privacy settings Ms. Duncan and Mr. McCormick had used to hide posts from their fathers. Facebook's online help center explains that open groups, as well as closed groups, are visible to the public and will publish notification to users' friends. But Facebook doesn't allow users to approve before a friend adds them to a group, or to hide their addition from friends.
FB's settings aren't ironclad in such a way that a FB friend who is careless, stupid, or malicious can't reveal something secret. Mr. Acosta didn't grasp how FB works:
"I was figuring out the rules by trial and error," says Mr. Acosta.
It's not worth having a destructive secret anymore... too hard to conceal it.
You can set your privacy, so that you can not be tagged i a photo or added to a group without your permission.