In Henderson v. Harnischfeger Corp. (1974) 12 Cal.3d 663 involved strict liability for defective products, the parties agreed the jury instruction in question was erroneous. The court concluded the error was prejudicial because the jury was instructed both that the plaintiff had the burden of proving he had not assumed the risk of the claimed defect, and that the defendant had the burden of proving the plaintiff's awareness of that defect as part of the defense of assumption of the risk. ( Id. at p. 671.)