I am interested in this disarming requirement.

Ideally, I would arm my system as the previous pilot is on approach, with the plane facing the runway, downwind of the judges chair. Arm the system, engage my throttle cutoff, and pass yo my caller. Would this be allowed? When and where does the restraint rule begin and end?

I think things should be equal with wet fuel planes; neither should be running/armed in the pits without a restraint - that's common sense, but we need clarity as to exactly when and where this new rule comes into play.