>>>Has this ever happened to you? I'm in the process of clarifying specs, by email, with a government client. I sent a list of questions, requesting they address them. I received my answers, only to find that they CC'ed a dozen or so end-users of the application I am to be upgrading, and included my list of questions.
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>>>Now, I'm beginning to receive messages from the end-users, providing me with their personalized wish-list, all because my client was gracious enough to provide their end-users with my email address!

This has happened to me, and my response was to index the wish lists, together with notations as to the source, and submitted an RFC proposal to the PRIME, and asked them to check off which should be included in the final revision. Sometimes surprisingly I was able to enlarge the scope and thus earnings. But, I never responded to the end users, other than to clarify a wish list item.