What is the difference between a reasonable and unreasonable plaintiff and a reasonable plaintiff under a "reasonable implied assumption of risk" approach?

2 In Ordway v. Superior Court, supra, 198 Cal.App.3d 98, 243 Cal.Rptr. 536, the court suggested that the differentiation in the treatment accorded reasonable and unreasonable plaintiffs under an approach viewing "reasonable implied assumption of risk" as a complete bar to recovery was only "superficially anomalous" (id. at p. 104, 243 Cal.Rptr. 536), and could be explained by reference to "the expectation of the defendant. He or she is permitted to ignore reasonably assumed risks and is not required to take extraordinary precautions with respect to them. The defendant must, however, anticipate that some risks will be unreasonably undertaken, and a failure to guard against these may result in liability." (Id. at p. 105, 243 Cal.Rptr. 536.)