Have you ever noticed how easy it is for people to say No in a shopping situation? It's almost automatic! Of course it is just natural shopping behaviour that comes from their fears. They fear meeting an un-professional or pushy salesperson, fear making the wrong decision, and fear paying too much.
It's like they arrive at the dealership with their quiver filed with “Nos” just ready for the questions they expect to hear. If you ask those questions then they will give you a predictable response - a NO.