> The statute applies to "confidential communications" -- i.e., conversations in which one of the parties has an objectively reasonable expectation that no one is listening in or overhearing the conversation. See Flanagan v. Flanagan, 41 P.3d 575, 576-77, 578-82 (Cal. 2002). A California appellate court has ruled that this statute applies to the use of hidden video cameras to record conversations as well. See California v. Gibbons, 215 Cal. App. 3d 1204 (Cal Ct. App. 1989).
If there's a reasonable expectation of privacy, all parties must consent to the recording.
Not sure referring to California laws follows here. It's for a different reason.