If a lawyer enters into a business deal with a client in violation of Rule of Professional Conduct 3-300 (i.e., without fair and reasonable terms, disclosed in writing, advice that client may seek independent legal advice, and client consent in writing) there is a presumption that the attorney exercised undue influence over the client, rendering the transaction voidable by the client. Here, the district court erred in ruling for Schrader Cellar the client, on summary judgment as there were triable issues of fact as to whether the terms were fair and fully disclosed.