Can a witness be called as a witness even though there is no action pending?

"[T]his is a law primarily to prevent the corrupt interference with the administration of justice. Its purpose is to go back as far as necessary and say in effect that any attempt to so influence prospective witnesses that the truth will not be presented in anticipated litigation is felonious. . . . It is the intent of the person interested and his purpose and design that is decisive of that question. True, a person cannot be a witness unless there is an action pending, but a person may be about to be called as a witness even though no action is pending." (People v. McAllister (1929) 99 Cal.App. 37, 40-41, 277 P. 1082, 1084.)