Pete, what happens when you meet the fastest boats after they have rounded or, heaven forbid, you are lapped and get to the gate at the same time as they? Not unrealistic in a mixed rating fleet where skill levels and boat speeds vary a lot? I was very uncertain about what to do in situations like that (yes, I have been lapped). Fortunately, the more experienced guys treated us more like an obstacle on the course than competitors and was really nice. If the rules took no more than 10-15 minutes to learn and understand, like in many other sports, my initiation would have been far less stress/angst filled.
I think Jack pointed out some important things in his post.

Simon, I really dont think the discussion here goes around finer points. The downwind rounding is one of the fastest and most complex situations you get on todays course. As the discussion here have showed, it is not very clear and widely understood what the rules say you can and shall do. If it was clear, surely the correct and full answers would come pretty immediately? I have scratched my head over the explanations and implications here as I am certain many others have done. Dont you agree that the rules are rather complex?

It is probably pointless to take the "rule complexity" discussion much farther. But it sure would be nice to have some open but experienced minds look over the rules and form much simplified alternative. Who knows, it might even work very well. Gurra is looking at it, and I know some others also are thinking along the same paths.