Yes, some backup cameras do record. In fact, every skEYEvue vehicle camera that we sell at skEYEwatch (including backup cameras) record video surveillance to an onboard mDVR. This is regardless if the vehicle is traveling in reverse or not. Our cameras are always recording!   On the other hand, many factory installed safety backup cameras do NOT record in most standard consumer vehicles.   However, there seems to be a promising future for built in surveillance cameras in modern day electric vehicles such as Tesla's Sentry Mode.