If a woman finds herself back living with her parents as a single mother, the Sin Sod insures that there will be some money/land in the family to support the family. Thai society also dictates that the older a Thai woman gets the harder it becomes for her to find a job, let alone a well-paid one. So again, should she find herself alone in the future, at least the family will have some money put by for some inevitably rainy years ahead.