Generally not, but it's depending on the prospective client, where they came from, and what the project is.

If it's someone who just moved into town and bought a house that's of the type we typically work in, and got my name from another executive at the company they just joined, I will absolutely do what I can to take care of them, while still making money (although not as much as if I had sold the gear, obviously). Almost never will they have EVERYTHING needed for their installation, and typically taking care of this less-profitable project leads to a relationship that provides years of business.

If it's some random guy who has a gear list from AVSForum and has dropped a form email into my "contact us" page from the website (along with doing the same to probably a dozen other places), then I will return the call, ask a lot of questions, and help them to understand that I'm probably not the right fit for their project.

I've spent a lot of time thinking about how my company presents itself specifically to ward off tire-kickers and "value" shoppers. A previous company that I worked at was always worried about losing the "bread and butter" projects (single-room media systems ~$10k) by appearing too high-end, so we got a lot of these sorts of inquiries (how much to install my new high-end Vizio and Klipsch package from black friday?). We get almost none of them at my current company.