Is a defendant obligated to protect a plaintiff from harm as a result of their actions?

"[T]he question whether the defendant owed a legal duty to protect the plaintiff from a particular risk of harm does not turn on the reasonableness or unreasonableness of the plaintiff's conduct, but rather on the nature of the activity or sport in which the defendant is engaged and the relationship of the defendant and the plaintiff to that activity or sport." (Knight v. Jewett, supra, 3 Cal.4th at p. 309, 11 Cal.Rptr.2d 2, 834 P.2d 696.)