I'm going to step away from my usual Libertarian roots and side with Pam on this one. It's important to remember that we have to work within the system we have, at least until we can change it.
The system we have has the State licensing Skippy and then doing nothing to rein him in. The rest of us daily get requests to do everything from working free, to violations of ethics, to outright fraud.
As long as appraisers are licensed, mortgage brokers (for the most part) are not, and many loans are made in a way that pays the loan processor a commission we will have problems. However, if enough of these guys get bit, then those problems will surely diminish.
Just one thought on the side of Roger and Mike, however...
Going for the fruit at the bottom of the tree makes sense to me... or even that laying rotten on the ground. If you do an appraisal of an address where you come in much below the one done last year, does that necessarily mean that the appraiser was Skippy? Maybe market conditions were different then. Maybe, even if market conditions were not different, the prior appraiser had access to a different set of comps than you have today. And, it could just be a difference of opinion, even with the same data. Therefore, I'd advise not swamping the system with questionable stuff and picking the most agregious cases to send in.
As for sending in requests for comp checks, that might actually be better than the scenario above. What do you have? Usually, it is a request for pre-determined value... why not try to nail a few of the people who honored that request?