What is the meaning of section 820.2 of the California Tort Claims Act?

Notwithstanding all of this learned written material, the meaning of section 820.2 is still not entirely clear. And in many situations and under evidence such as that which may be produced at the trial of this case, it may very well be that the case will fall within one of those situations where section 820.2 does not apply. Let us illustrate: Suppose it should develop that respondents have refused to exercise Any discretion in the matter of supervision of safety of adolescents attending Sacramento High [25 Cal.App.3d 275] School--even an abused discretion, knowing that gangs of marauding hoodlums are endangering lives; that they have just turned their backs to the whole problem. Would section 820.2 apply? We would not so rule. Or suppose that at the time this incident took place, respondents had already exercised a discretion in the matter and had formulated a plan which respondents then put into operation negligently. Would section 820.2 clothe respondents with a protecting cloak of immunity? (The court in Costley v. United States (5 Cir. 1950) 181 F.2d 723, construing the Federal Tort Claims Act (similar to California's) did not think so. And see Sava v. Fuller (1967) 249 Cal.App.2d 281, 291, 57 Cal.Rptr. 312 (hg. den.).)