What obligation does a parent have when they fail to return a child to the child's mother?

While this obligation has its genesis in the moral reprehension of deadbeat parents, its application is much broader. Liability is not necessarily based upon fault or wrongdoing; absent parents may be obliged to pay even where their former or current spouse deliberately concealed the child in violation of a court order. (In re Marriage of Comer, supra, 14 Cal.4th 504.) The rationale, "quite plainly, was to recoup welfare costs from the absent parents of children being given public assistance." (Clark v. Superior Court, supra, 62 Cal.App.4th at p. 579.)