LackOfOnSiteCustomer unfortunately does occur. This is certainly not ideal but happens frequently. In these cases someone from with the development organisation can act as a proxy for the customer. This scenario also raises the question of what processes should be employed to counter the disadvantages of having no OnsiteCustomer to resolve disputes or clarify questions that inevitably arise during development. -- KeithPitty
The CustomerProxy should be an InteractionDesigner. And actually, the project should be better off with an interaction designer than an actual customer. Of course, the interaction designer will probably quit if she doesn't have any access to customers.