Final answer:
The circumstance that does not require agent disclosure is when Marty is representing Dwayne in both the sale of his current home and the purchase of a new one, as this is a dual agency situation that is often lawful and does not inherently involve a conflict of interest without specific laws stating otherwise.
Step-by-step explanation:
In the context of real estate transactions, agent disclosure is a legal requirement where an agent must disclose certain conflicts of interest to their clients. Reviewing the provided circumstances, the one that does not typically require agent disclosure is when Marty is representing Dwayne in both the sale of his current home and the purchase of his new home. This arrangement, known as dual agency, is legal in some states as long as it is disclosed and consented to by all parties. However, it does not inherently involve a conflict of interest that requires additional disclosure unless specific laws or regulations dictate otherwise.
The other situations involve potential conflicts of interest where disclosure is typically required: Sean, as a licensee owning investment properties and selling one, would need to disclose that he has an interest in the property, while Gary, being a shareholder in the title insurance company selected by the buyer, should disclose his interest in the company. Megan's case, where she has listed her brother's townhome for sale, would also typically require disclosure that she is related to the seller.