It's kind of a tricky area if you're at a dive site and you see people violating standards & not following appropriate procedures. As a professional, you should speak out and bring up the issue with the other divers even when they're not associated with you.
Actually, that's precisely what you DO NOT want to do if the people are not associated with you or your shop and you want to keep yourself out of court. Aside from instantly making yourself a target, you will lose the legal shield you enjoyed right up to the moment you decided to intervene.
California courts recognize that a person generally does not owe any duty to control the conduct of a third person or to warn those endangered by such conduct.
Zelig v. County of Los Angeles, 45 P.3d 1171 (Cal. 2002).
The California Supreme Court stated in
Zelig that a duty to warn or control only arises under limited circumstances: "A duty to control the conduct of another or to warn persons endangered by such conduct may arise, however, out of what is called a 'special relationship'. Such a duty may arise if '"(a) a special relation exists between the actor [you] and the third person [the idiot teaching wrong standards] which imposes a duty upon the actor to control the third person's conduct, or (b) a special relation exists between the actor and the other [the poor students] which gives the other a right to protection." ' Id; see also
Hernandez v. City of Pomona (1996) 49 Cal.App.4th 1492, 1499, 57 Cal.Rptr.2d 406.) ' "This rule derives from the common law's distinction between misfeasance and nonfeasance, and its reluctance to impose liability for the latter." ' (
Hoff v. Vacaville Unified School Dist., supra, 19 Cal.4th at p. 933, 80 Cal.Rptr.2d 811, 968 P.2d 522.
Per se "special relationships" recognized by the Court in other cases include parent/child relationships and psychotherapist/patient relationships. The Court also found a special relationship to arise when a sheriff expressly promised a particular citizen to inform her when a certain criminal was released on parole. From these circumstances and from general case law, one may conclude that a special relationship can arise when (1) a recognized legal duty exists, and (2) an actor voluntarily obligates himself/herself to the duty. I am unaware of a general legal duty of divemasters to the general population to warn them or intervene when the DM sees a standards violation.
Once you stick your nose into something, you assume whatever duty of care applies to the situation. If you are a professional or quasi-professional (e.g. a divemaster) you assume the duty of care applicable to such a professional, which is invariably more stringent than the duty owed by the average joe on the beach who undertakes the task.
If it is any comfort, there is no reported case in the United States where a DM has been held liable for an accident when s/he was merely a bystander (at least that I have found in my Westlaw searches) .