How to handle a situation where the client does not want to surface and address Risk in the project?

we should do project according to Client/Customer requirements/Objectives besides any A requirements conflict is generally resolved in favor of the customer, therefore all what we can do here is to asses the risk and document it in risk register then show the customer how it will impact in project objectives and what's contrarians ..  

In this case, i would show him the impact of the risk to objectives and deliverables.