Susan is worried that her boss at work can see her Facebook posts so she's changed her settings to friends only. Is that safe enough? Leo says that will work, however, Facebook does make mistakes and they do from time to time reset privacy settings without warning. Even Mark Zuckerberg's personal posts were outed by a glitch a few months back. So it's best to always consider a post she makes on social media to be out in the open.
Leo also says it would be a good idea to read up on her company's social media and internet policies. If she's using a company computer, they have the right and ability to read what she's doing, even if she's trying to post privately. They may have snooping software to look into that. So Susan should be aware of that as well.