Walk Away. Good advice? or Financially Irresponsible?

There is an article in the AARP Bulletin that was published in May 2011 (Vol.52, No. 4, page 22) titled: "Your Money-Financially Speaking - Picking the Right Options" by Jane Bryant Quinn. She discusses nine options for handling housing in retirement years. Option No. 6 is "Walk Away." She says, "If you can't afford the house and can't sell it for enough to pay the mortgage against it, walk away and rent. Don't run through your retirement savings in a futile effort to hold on."

Is this good advice or an indication that it has become acceptable for mortgage holders to be financially irresponsible?

What do you think?