Most of the people that I know who walked away from their mortgages did it for financial reasons that had little to do with their ability to pay. Most of them got away with transferring all of their consumer debt into their homes, walking away and saddling the rest of us with the cost of their new cars, expensive clothes, extravagant lifestyles, etc. etc. etc... The consequences to many people who did this were negligible.
There were people on the radio encouraging homeowners to default, claiming that their credit ratings would only take a hit for a few short years even with a foreclosure on their records.