Okay, I have been experiencing trouble since the company I work for allowed free housing consultations. (I work for a home designing, construction and renovations company)

We have been getting a number of clients that like to ask for materials from us such as drawings, floor plans, quotations, copy of contracts and alike, which is somewhat fishy, but also understandable when you're a first time builder.

We struggle to make prudent and customer friendly decisions as well -- in this light we only release floor plans and quotations prior to an engagement fee. We want to protect our intellectual property and hard work, but since we know that construction is a suffering industry, we try our best to please our customers.

We are experiencing a customer who came to us, had a house quoted, then dropped us, and then came back and is now having a resort quoted. Fishy, much?

I guess my question is: can someone recommend a more organized way to handle this? We don't like being abused, and I need to identify clients that are actually interested from those who are just plain abusive or have another agenda in mind --- and how do I handle them/turn them away?

The process is getting be frustrating because we're turning in to a quotation mill with less sales..

I definitely appreciate any detailed advice that you guys may have to recommend.
Thank you in advance.
Additional Details
We're under gong some major changes in management and system. Basically, the company has been around for some time, but its been running like a mom and pop joint.
Now we're trying to systematize everything so we can branch out gracefully with a more professional approach to handling clients.
I work closely with the board -- and I have influence on their decisions. :) I just wish I knew better....
Thank you, Archer. :)