If they are a facilitator, then almost anything goes.
If it is the seller you are talking about then there is no confidentiality.
In the case of the seller or facilitator, while not illegal, I find it unethical.
Buyer's as a side note: Please, please, take the time to understand agency relationships. More buyers are less than satisfied because they do not understand the relationship they have with their agent.
As a matter of fact, there are a lot of people out there gathering information about every sale to use in their statistics books. Don't be surprised if someone approaches you.
A lot has changed in my lifetime, (I'm an O.F.), when I was young, people talked: Didn't worry about it. Nowadays; people are afraid to say the wrong thing or talk to the wrong person. Too much paranoia out then; rightly so.
Good luck and may God bless