What if the client owns the same or better camera than you do? Are they hiring the camera or the expertise? What if this subject comes up on a shoot, because they do, in fact, have a better camera than you do?
When I was only shooting 4x5 for architecture, some of my best architect clients owned "better" view cameras than I did and to top that had taken university classes from me. So they knew how to use them. I used an ancient and cheap Calumet Widefield for many many years and made no apologies for it. They weren't hiring a camera, but my 30 years of experience mastering the camera, the lighting, my vision and lastly my knowledge of design competitions and the magazine business to help them win awards and get published. It is no different now. I have one client that just bought a Nikon D3X and another with a Hassleblad Flexbody/39MP back. I use a 5DII. I have large shoots scheduled with these two clients this year. It isn't about the camera-never was and never will be. You bring allot more to a shoot than just an expensive camera.
Over the years teaching university classes and workshops, I have had many students with better equipment than me too. Does that make them better students? Sorry. Hard work and vision makes better students-not cameras. Equipment can be a limiting factor. You are not going to get largeformat quality if you use a 35mm camera, but the greatest limiting factors are lack of vision or expertise.