I doubt that FAA has much interest in where that line is drawn, as it doesn't appear to bear very much on their charter to maintain order in the airspace that is occupied by regulated aircraft. I expect this is an area where AMA could set the standard and have FAA's blessing, to the extent it might matter to the feds at all. Won't happen if AMA's position remains as nebulous as it is now, though. This is a matter for AMA's Insurance Committee to address and make recommendations to the EC for resolution, rather than wait and see what FAA will do.