I would argue with the NY trooper. I checked here in Missouri and the trooper on the phone asked how many wheels and I told him three. He said motorcycle and a helmet is required. I then told him about the car seats, steering wheel and shoulder belts. His next question was how many wheels......... MOTORCYCLE and a helmet will be required.
I know some states have exemptions for larger etc that take the trike out of the normal motorcycle laws, but most states with helmet laws require the helmet regardless seating and steering nature of the vehicle.
So if the trooper says helmet, and it's a helmet state, I personally would not dispute his request and I'd helmet up. I would not try to prove a point on the road, but read and check the laws without the trooper present etc.
