Not true? There have been plenty of reported cases that it is a fact. And even the banks are walking away from foreclosed properties,
If I purchase a home for $500,000 and take out a $400,000 mortgage and the value of the property declines to $200,000, I would seriously consider walking away from it. It would be difficult to sell and I would have to make up the $200,000 to pay off the mortgage if I sold it for $200,000. It is the reason why the Adminsitration has established a program to address this issue: Obama Mortgage Assistance Plan