Why is my brother asking me to sign this document?

My brother, who's a real estate broker, asked me to sign a buyer-representation agreement before he helps me find a house. I trust him completely. Why do I need to sign some paper? The short answer: to protect both of you. The buyer representation agreement spells out many aspects of a broker-client relationship, including how he will be compensated, your agreement to work exclusively with him, and his agreement to help you find a property and negotiate the deal. In addition, as a member of the National Association of REALTORS®, your brother is obligated to comply with NAR's Code of Ethics, which sets strict standards on REALTORS®' duties to clients and customers, the public, and other REALTORS®. The code requires REALTORS® to assure whenever possible that agreements-like a buyer representation agreement-express the specific obligations of the parties in writing and in clear and understandable language.