Does the collateral source rule apply to a tortfeasor?

Although the strong adherence of California courts to the collateral source rule cannot help but be recognized, in this case there is the competing interest, also well recognized by our courts, that a defendant may not be subjected to double liability. While the court in Helfend made clear that a plaintiff is not to be penalized for his own providence, it also emphasized that "[i]n reaffirming our adherence to the collateral source rule in this tort case involving a plaintiff with collateral payments from his insurance coverage, we do not suggest that the tortfeasor be required to pay doubly for his wrong once to the injured party and again to reimburse the plaintiff's collateral source . . . ." (Helfend v. Southern Cal. Rapid Transit Dist., supra, 2 Cal.3d 1, 11, fn. 15, 84 Cal.Rptr. 173, 179, fn. 15.)