Whirly is absolutely right. We need to bury the CAA in objections based upon the issue she raises.
It is particularly relevant for instructors carrying out training. During training, you are only supposed to land at a licensed airfield. This means that during training you should not land at a confined area off airfield. If away from a licensed airfield, the "500 ft minimum height" version of Rule 5 would mean you had to break off your confined area training at 500 ft agl - hardly very realistic or useful training?
