> Inside of a private car with the windows up isn't public.
If it was your car and someone got in and recorded you, then I'd say that's more clear cut. But if you get into someone else's car do you have a reasonable expectation of privacy?
Since you're technically hiring that person and their car to provide you a service, they have to disclose up-front if you're being recorded. In addition, just because you were being recorded doesn't mean the driver has the right to publicize the video. That requires additional consent unless it's a matter of public record.
Also, for all we know there could be a sign in the black car that says, "Smile you're on candid camera!".