You can't accidentally share a private fork any easier than you could a new repo. If you try to make a private fork public in GitHub there is just a message tha

You can't accidentally share a private fork any easier than you could a new repo. If you try to make a private fork public in GitHub there is just a message that "For security reasons, you cannot change the visibility of a fork." As far as I know the article's example of 'a developer forks a private repo and makes it public' is not possible in github.