In Ferraro v. Southern Cal. Gas Co. (1980) 102 Cal.App.3d 33, plaintiffs' property was destroyed by an explosion and fire; they were reimbursed by their insurance company for the property damage they suffered. (Id. at pp. 37-38.) The insurance company filed suit against defendant gas company, and plaintiffs later filed a separate suit against defendant. After finding that the impermissible splitting of the cause of action was waived by defendant's failure to object, the court of appeal held that the insurance proceeds collected by plaintiffs were not a collateral source. (Id. at pp. 46-47.) As the court explained: "A collateral source is one ' "wholly independent of the tortfeasor." ' Therefore, since 'to subrogate is to put in the place of another; . . .' when an insurance carrier becomes subrogated to the claim of an insured against a third party tortfeasor, the payment of insurance proceeds is no longer a 'collateral source.' To conclude otherwise would violate the rule against double recovery, since both the subrogee and the subrogor have a right of action against the tortfeasor." (Id. at p. 47.)