Replaced Zone with Rounding or Passing ( = from the time her proper course is to begin to manoeuvre to round or pass...) for windsurfing, could probably work for some windsurfing events, but for the standard fleet racing, it certainly causes more trouble than the standard concept with the Zone.
I think that more modern (flexible) kite and wing rules recognized the trouble and "moved back" to the Zone concept.
It creates much more predictable and clearer situations and is easier to decide what to do, from the point of view of competitors.
The moment when a windsurfing board starts to manoeuvre to round or pass might be, in some situations, "clear" for the closely positioned observing judges, but it can also be almost impossible to see and establish from the point of view of another competitor.  (Typically, at the leeward mark approached by boards on different tacks from 2 pretty wide angles)
Establishing the moment when a board reaches the zone, together with the concept of  RRS1 8.2e) (=solving the doubt if a boat obtained or broke an overlap in time), offers a predictable and safer solution. 

What I am saying is that it is more complicated than simply having a gravitational force component parallel to the local surface of the water.  Surfing, as a general phenomena, is defined and understood.  Where it isn't defined is in the RRS.  Unfortunately, this forum is not the place for the very long and very deep dive explaining the physics of surging, surfing, and planing.  But to me, the take away is that we need to understand the difference between surging, planing, and surfing and when each of these is possible to be able to properly interpret and apply RRS 42.

Wow Paul ... that must have been a lot of work (and moving forward as the working out the kinks phase begins). 

Congratulations!

Ang

Thanks Ben ... yea .. you asked how the reasoning would go and I obliged :-)

I don't think this is quite right.  It is making a RRS 2 protest look like a RRS 69 hearing which it is not.

I agree that a breach of RRS 2 that affects the fairness of the competition on the water will usually be accompanied by a breach of Part 2, but even if it is not, a breach of sportsmanship that affects the fairness of the competition is nevertheless an incident in the racing area and requires a hail of 'protest' and if necessary display of a flag.

Agree, and in OP case, I think we have

Boat B broke RRS 2.  RRS 36(b) does not exempt a RRS 2 breach.  On valid protest B should be DNE.