What is the definition of a "vulnerable" victim of a criminal threat?

cases. Vulnerability means defenseless, unguarded, unprotected, accessible, assailable, one who is susceptible to the defendant's criminal act. An attack upon a vulnerable victim takes something less than intestinal fortitude. In the jargon of football players, it is a cheap shot." (People v. Smith (1979) 94 Cal.App.3d 433, 436.) Here, the offense of making criminal threats, as established in section 422, targets "those who try to instill fear in others." (Felix, supra, 92 Cal.App.4th at p. 913.)