"Everyone" given special permissions in CIFS share
When I create a new CIFS share, the "Everyone" account is given special permissions to "Delete subfolders and files". This means that, if you create a share, and you allow guest access, then anyone can delete all of your things. Even if you don't allow guest access, the permissions are still set that same way.
It's easy enough to fix this after-the-fact by changing the permissions, but it's kind of a pain when you've got a handful of shares, and if you miss one, all your data can be deleted by anyone.