Have you ever had to explain to a customer that 'Hosting' and the domain name 'registration' are two seperate things. And that one does not automatically come with the other?
That kind of thing happens in all industries. Insufficiently knowledgeable customers will assume things go in a manner that suits them (wishful thinking basically) only to turn against the provider when their dreams are shattered. That's often the first time they read the TOS for more than a couple of seconds too.