we are not immune but their are a couple of salient points of structural difference in the way the US and Aust systems work
in the US the owner of house doesn't carry the debt after defaulting unlike here. For example in the US if the owner of the house can't meet repayments they are able to leave the house and not look back (to bad so sad - see ya clause). That leaves the house on the banks books as an asset and the loan as a liability. The US has an oversupply of housing which means the banks can't shift stock ie sell houses as there is no demand.
Here if you can't meet your repayments you can't just walk away from the debt on the house, it stays with you. The bank might forclose and sell the house but what ever is not made up by the bank they then come after the owner for recompense.
Also the supply and demand issue - in Aust we don't have enough housing to meet demand - demonstrated by vacancy rates on rentals. So people might become fussier about the price they are willing/afford to pay but they still need to live somewhere.
So we could get into a mess like the US but it is much more difficult to do and not as likely. Hell anything is possible though.
