The possibility of the unjust enrichment of the insured results from the common law principles under which the insured is entitled, where a third party causes an insured event, to sue both the third party [FN80] and the insurer, [FN81] *151 both of them owing a legal obligation to the insured. This means that the insured might be unjustly enriched only where he has two (or more) debtors on the same loss - the insurer and the third party. If only one of them is legally obliged to pay and the other is not, there will be no possibility of the unjust enrichment, and therefore there should be no subrogation right. Based on this analysis, the insurer should not be entitled to subrogate where he pays the insured voluntarily.