Whether prices are rising, stable, or declining, appraisers should have a grasp of why that is, and be able to relate it to population, trends, business growth or stagnation, as well as any influence of interest rates or avail financing. Add in that different segments of the market can perform at different levels in the same region within the same time frame. Prices may be rising for lower price starter homes, yet stable at the upper price points, for example. How astute an appraiser is about these factors is part of competency.
However, whether a market is rising, stable, or declining, a pushed value or number hit /agenda driven appraisal is easy to spot, if one knows what to look for. It actually is achieved by doing just what the OP described; by fudging adjustments ( or ignoring a property condition ) and by relying on less similar comps instead of the more similar comps, when prices of the more similar comps are not leading to the desired target.