I have checked with several attorneys. They are mostly scare tactics used by large companies and appraisers. Attorneys know they don't work in court and advise as such. They are typically enforceable in the entertainment industry or other such business where they 'own' you and your personality. Ignore it. Any appraiser that makes it a part of working for them is probably not confident enough in their own clients to hire fee appraisers or trainees anyway. Its stupid to work for AMCs that require it anyway. (or any AMC's for that matter - they pay low fees and hire terrible appraisers).