Here's something I haven't seen that often.
It's a unanimous opinion by the California Supreme Court. Or, at least, the six regularly sitting justices of the California Supreme Court. Justice Klein is sitting by designation from the 2/3. She dissents. Joined by no one from the regular Court.
I can understand why that happens. After all, it's a significant case on the merits. The question comes up all the time in personal injury cases: When someone's injured, and his health insurance company pays the full bill and gets a negotiated discount, does the plaintiff get to recover just the amount paid or the full (undiscounted) amount? So even though, in a less visible (or significant) case, a justice sitting by designation might simply sign onto an opinion joined by all the regular justices, you can see why Justice Klein departs from this usual practice. Though why other justices might have done something different as well.
As for the merits, there are reasonable arguments both ways. After all, the whole point of the collateral source rule is that the tortfeasor shouldn't benefit from the fact that the victim purchased insurance; that's why he still has to pay for the medical expenses even if the victim wasn't out of pocket. On that same theory, the tortfeasor should pay the full amount. That's Justice Klein's argument (in a nutshell).
But the Court holds that discounts are different; that it'd be a windfall for the victim to recover extra money just because his insurance company got a discount. Which has a lot of sense behind it.
Critical legal scholars might have an interesting take on the Court's holding, though. Since it seems perfectly designed to protected vested interests -- e.g., making sure that the insurance company (which typically gets subrogation rights) gets fully reimbursed -- while simultaneously protecting other large entities (e.g., often, defendants liable for personal injuries, or their insurers) from incurring additional expense. The loser? The individual plaintiff. The result's perfect for insurance companies, both on the medical side as well as on the liability side. Whereas the result's far from perfect for the individual plaintiff himself.
That doesn't mean, of course, that the decision is wrong. But if you're an academic, particularly with a certain take (e.g., a critical or legal realist), you definitely might use this holding as an example of a certain approach to the law.