kiwi chick,
When was it ever a requirement to give a position report every 10 minutes. That was precisely part of the point of my post. Unless you are operating inside an MBZ there are no prescribed time frames to make position reports. Yet it seems that some pilots see the need to continually broadcast their position to all and sundry at very regular intervals no matter where they are.
Part of the lookout when carrying out stalling or aeros is to make sure that you are clear of such areas like you mention, i.e a scenic flight path or aircraft popping out from behind Kapiti as you so eloquently put it.
As for the very unfortunate Massey accident. We will probably never know the full story. A radio call may have helped, however I suspect that both pilots were aware of each others presence in that area. A vigilant lookout from both parties would certainly have helped avoid this accident.