The patronizing we (also known as the kindergarten or preschool we) is sometimes used in addressing instead of you, suggesting that the addressee is not alone in their situation such as "We won't lose our mittens today." This usage can carry condescending, ironic, praising, or other connotations, depending on intonation. "Aren't we looking cute today?"
The hospital we is sometimes employed by healthcare workers when addressing their patients; for example, "How are we feeling today?"
In your case I would say the "patronizing we" used to include the server in the group at the table (or the table in the "family" of the restaurant)