In the US (if I've understood correctly) anyone with a 100% mortgage and rapidly falling house prices (potential negative equity) simply sends back the keys and the debt is cleared. Don't fight forces, use them R. Buckminster Fuller.
So the lenders who never should have lent to people who never really could afford to buy take their lumps, without destroying the fabric of the neighborhood. And it seems like if the house value continue to slump, the "fair rental value" could drop with it, putting the prior owner of the house in a position to save up a down-payment toward getting into the market for a house they can afford. Utsukushikereba sore de ii