When assisting buyers in their search for a property - a house, condo or townhouse - a Realtor must fulfill a set of obligations. These obligations differ, depending whether the Realtor is assisting his/her client, or a customer.
A client is someone who, by signing a Buyer Agency Agreement, hired the real estate professional to represent him/her in the process of searching for a property and negotiating the purchase (or lease).
A customer is someone who has chosen not to be represented. While the Realtor must treat everyone, client and customer alike, fairly and honestly, it is a client who is represented, and whose best interest is always protected. In a transaction where the buyer is not represented (treated as a customer) the Realtor must look after the seller's best interest.