I am a procurement attorney in an open concept office, but the type of legal advice I give does not require the nature of confidentiality that you are suggesting. Our office only has procurement attorneys and contracting staff. We do let people know if we are having outside visitors, but that is quite rare.

Curious what protections you office put in place? How do you hold the line on not talking about private info relating to criminal matters or civil cases? Did your supervisor help set up boundaries or rules for the office? Did you do anything to set expectations with paralegals? Do you take calls at your table or cubicle - or do you always book a conference room?