I think the whole system has failed these kids, they have been treated like cattle, by people who appear to care not one single jot how they are feeling about all this, or how it is affecting them.
I disagree with you, but I am starting to see your point. I'll elaborate on both, but you are free to ignore either.
The mother played the system to the detriment of everyone in the system. It only "failed" in the sense that it was not set up to deal with her particular level of crazy. Many people cared about these kids and they were forced to work outside of their normal functions by the machinations of the mother. The mother failed her daughters, and the system was not prepared for such an epically selfish mother.
But I see your point that the police could have done a better job. I really think they would have been ostracized for doing so, but they could have removed the press from the scene before taking the children to the airport. In the US this would have been very difficult and I imagine it would in Australia as well, but it would have been the only way to take the kids into custody without force. Now, knowing that removing the press is the only way this could have gone smoother, is that really what we want to encourage our police to do? I don't think so, but you are concerned by the show of distress put on by these girls, so maybe you do.