Appraisers?

Have any of you experienced appraisal values being reduced by an arbitrary 20% because the market is declining??? With a reduction in the number of sales, and the declining 0prices, we are seeing some very arbitrary judgments in overall value. Just as we as REALTORS(R) have a fiduciary duty to price our listings properly, I would hope that appraisers would not be adjusting values just to stay safe! We are in a market where no two homes are alike; many adjustments must be made in order to arrive at comparability; and sales are few and far between. With everything else we are dealing with, it seems it is more important than ever to provide comps that "might" be used just to give an appraiser (particularly an appraiser from another area) a foundation from which to start. Any real world stories out there?