Depends on the state laws....as far as I know WA state and (I think) VA/DC are two party consent states for audio recording....meaning the subject being recorded has to know and agree to it.
Even in WA state, in public, no consent is required.
I'm tired of saying this.
I provided the link to the quote below early in this thread. Please read the whole thread before commenting.
Just because it is a restaurant, does NOT mean that one does not have a reasonable expectation of privacy insofar as this law is concerned in California, your assertions notwithstanding.
California's wiretapping law is a "two-party consent" law. California makes it a crime to record or eavesdrop on any confidential communication, including a private conversation or telephone call, without the consent of all parties to the conversation. See Cal. Penal Code § 632. 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 you are recording someone without their knowledge in a public or semi-public place like a street or restaurant, the person whom you're recording may or may not have "an objectively reasonable expectation that no one is listening in or overhearing the conversation," and the reasonableness of the expectation would depend on the particular factual circumstances. Therefore, you cannot necessarily assume that you are in the clear simply because you are in a public place.
Source
It looks to me like the creeps in the California legislature have made it possible to cite the expectation of privacy in virtually every case short of a debating stage. Guess how a California judge would rule in a civil case about these recordings in abortion happy California? I think these courageous people are probably in trouble. Getting out of it won't be cheap. I think they knew that up front and did it anyway. It took guts.