In my opinion it seems very simple. Is the NEC a legal code in your area? If so, and if the job meets the NEC then it must be OK! No matter who wants what. If the NEC is legal code, then the NEC must be followed. IF the NEC is not legal code, then you must find out what (If any) rules/laws cover these issues. Then you would have to follow the rules/laws that do cover ths job.
