On the witness stand? Bob, you are entitled to your opinion. Is it supported by data? Have you ever been on the witness stand or observed another appraiser on the witness stand? Have you seen a situation where an appraiser had done a matched pair analysis, and was somehow glad that he had? I know this sounds like an argumentive response, it is not intended that way. I have been on the witness stand 1 time, and this topic (support for adjustment) never came up. I humbly submit that in most appraisals, the possibility of this happening is so remote that it is not a good idea to make decisions based on what would happen if called to the "witness stand". If anyone has real life experience to the contrary, I would be glad to hear what they have to say.
Is every adjustment guilty until proven innocent? Depending on the circumstances, it could be "wrong" to make no adjustment (busy street would be a good example). Does an appraiser need to somehow support and defend every addjustment that is not made? IMHO, it is desirable to be able to defend and support every adjustment with market data, but in the real world, the majority of adjustments are made based on knowledge and experience. Again, my opinion -- we are not helping new appraisers by trying to make them paranoid about the USPAP POLICE coming to arrest them.
I am trying to give advice based on experience. If they want Appraisal 101, they can read the text book.
It could be that this person has no idea what kind of adjustment to make, but I doubt that is the case. IMHO, they prolly know already that a busy street location is less valuable. I advocate a look at market data AND to use their knowledge and experience, don't sell themself short.