That kind of conversation develops as trust is built. I begin to communicate expectations the moment I begin communicating with another person. When arranging for a first meeting, I communicate that I will be there, and here's my phone number. "Please call if something unexpected is causing you to run late". Just with that sentence, I'm communicating what some values...integrity and punctuality. Also, by setting a date and time, and not just an "Oh, we'll touch base sometime that day", I'm also communicating that I value my own time, and respect other people's time.
The communication of values continues as I get to know people, and they get to know me. The communication of these values simultaneously communicates boundaries. These values become the "cultural norms" which are at the basis of relationships. When somebody asks a really probing question, I may choose to answer depending upon the level of trust established. Or, I may turn the question around and allow the person asking the question to share first.
All relationships are a dance. Values are continually communicated and become expectations of normal, acceptable behavior. Without getting to know somebody fairly well first, it would be awkward and relatively random to just call out or blurt out expectations on a first meeting. That is callow.