As the title says. I have a folder, which I added to my Shared Folder list under System Preferences > Sharing
that I do not want to broadcast publicly. I'm the owner of the folder and my access is "Read & Write" and the Everyone group is set to "No Access".
Using a second computer I can navigate to this share, logged in as "Guest", and I can still see and navigate this private share.
I removed all my shares, turned off and back on again (AFP file sharing service) and instead of defining my share points in the System Preferences, I used ⌘I (Get Info) and checked the "Shared folder" checkbox. I then applied the same permissions at the bottom of the Get Info window with the same results. I can still see and navigate the private share over the network.