Rob,
I would be my understanding that the so-called "comp check" does not have the intended use of establishing collateral value for a loan, and thus fall outside the scope of some mortgage law and regulation. As far as I understand it, the intended use of a so-called preliminary, limited, desktop or comp-check appraisal is the for someone like MB's to asses the feasibility of the deal. There are no other intended users, except the MB. The borrower is, as far as I can tell from your posts, not paying for this service, so when you said "their" appraisal, I don't see how you can claim this is the borrowers appraisal (they didn't order it, they didn't pay for it, they didn't engage in any deal based on it). It would be a RESPA violation to fail to provide a report copy if the borrower paid and if this is the appraisal that supported the loan.
I am also wondering if you think RESPA and Connecticut law limit the market to one opinion of value. Let's say, the first appraiser makes an error. Are mortgage brokers precluded from getting a second appraisal and sending along the loan documents with the second appraisal?