Not exactly. Techanically the client has to sign an

exclusive employment agreement with the agent before he/she can take you to a house to show it. 

But in many case, the agents are nice enough to not force the client to sign that exclusive employment agreement, like LZ did.  So cleint just walk away to save money is inappriopriate.

Of course, if the client is not satisfied with the service and want to walk away, they do have the right.