What concerns me is that this eminently sensible idea in principle will be used as a tool by CASA to continue the embuggerance of GA. For example, a simple check of a weeks fuel dockets, given you know the capacity of the aircraft, and you can pinpoint any large uplifts that might mean transgression of the reserve rule. Similarly FOI's now have an excuse to check your fuel state on arrival.
Furthermore, I fail to see how declaring a fuel emergency on track to Binjimup or some station somewhere is going to get you anything but a "show cause" letter from CASA.