Interesting question. I did some work where I included designers for all print related things and I would always introduce them to the client. Also, I've been the developer for a few designers and I always appreciated it when I got directly in touch with the client. It expands your network and you can list the project in your portfolio.

How would that work if you are subcontracted without the client knowing? Would you still be able to publicly show that you worked on a project?