Tony,
I disagree. Firstly we would get advance warning of that. Secondly they (the Indons and the Chinese) do not have the power projection capability to do what you say (short of a nuclear stike, but then everyone is a loser). Therefore it is highly unlikely. The financial thing might be a higher chance of happening, but as we have seen even with the GFC, whilst individuals do indeed suffer, life still goes on. Australia is indeed the lucky country in terms of natural defence. The only country at the present time that could invade us and sustain it and win would be the US. Things may change by 2050 with China (is that enough advanced warning? The latest Defence White paper is a good read if you can read between the lines).
And I actually like to think that the Chinese (and India) will actually be the saviour of Western society from the current war we are in. How is that you will ask? well lets just say that they are a-religious and their power and inflence might just stop the spread of radical islam that has as its goal to essentially take over the world! (Just like Pinky and the Brain, but a little more credible!). India did offer 120,000 troops for Afghanistan and with this number of troops the war would be over in 12 months. (The peace would take a little longer...) But this is untenable to Pakistan having Indian troops on its Eastern and Western borders... I digress.
Anyway i don't think the Indon or Chinese hoards will be coming to Australia in the foreseeable future. So I think the most credible threat that may require some survival techniqiues would be a natural disaster for the short to medium term. However even natural disasters are only localised (tell that to all but the two provinces in QLD declared natural disaster zones!) But I have been here in Townsville for two weeks and whilst we have had only two days of intermittent sunshine, life still goes on.
Maybe I am not an actual survivalist nutter after all!
Cheers
CB