Lets not argue - lets be practical instead. The "crowd" was small; it was across a considerable area of grass within the compound; there was a fence; there was a road with moving traffic on it. They came out of a convoy of cars, said goodbye to the escort and got on the plane.
Maybe they didnt even SEE the "crowd"; and if you read some of the posts on this thread, interest in Aus is so so small, its amazing that anyone, inc the media turned up.
Just a practical perspective.
That is SO TRUE! When I watched the video, it was clear that the "crowd" was so far away that there is no way the royals could have noticed them or expected anyone without a zoom lens to see them. No one was slighted!