Dont you just love local HD interpretations.... NOT!!!!
What I was told by my electrician that a gfi is only good if you have an active ground. Which if you are mobile, gfi does you absolutely no good. However if I am in an event, I usually find something to clamp a ground wire on. Also when you have fluctuating power as so many events do, those things will be popping off all the time. Check and see if ND goes by the national food service codes, because I know there is no requirements under the national code which gives you an arguing point. You'd be surprised what you can win when you know your stuff!!!! I get along good with my locals now, whereas we were enemies at first. Good luck with your locals.