[Robotbeat]

I wouldn’t consider the rocketry code itself a good argument. The model rocketry code, frankly, is biased hard against any kind of liquid (especially non-hybrid) rocket engines, so there’s not even really a way he could follow it with a liquid in any reasonable way.

(Which isn’t to say he couldn’t follow better safety common sense.)

[chipsa]

The model rocketry code is for model rockets, not high power amateur rocketry. Though the HPR safety code also isn't friendly to liquids, but partly because it still dictates commercially developed motors.