Today, home sellers in most states must now fill out a form disclosing material facts about their homes, and in some cases have to pay a fee if they don't. (rismedia.com)
In that case, being a transaction broker doesn't relieve you of responsibility to disclose material facts so I doubt the agency relationship would make a difference to a court. (toughnickel.com)
There's also the obligation to disclose any material fact which could effect the other party's decision to enter into the deal. (kevin.lexblog.com)