I can't speak for the mobbed up union states but I changed from the
inspector trade association (IAEI) to the contractor group (ECF) many
years ago and I talk to those guys a lot. (they are more fun) They get
a lot of basic theory in their CEUs these days and I have never met
one of them who was confused by neutral loads. It is dealt with
extensively in NEC articles 215 and 220. These are generally the
license holders but we also see a lot of journeymen.