There is a ground out to the radio chassis, but where does the radio chassis hook into the ground system of the car? All 4 tabs you screw it into are all plastic, not metal and not attached to the metal body of the vehicle. If you get a high end radio like an Alpine or such you have to body ground the radio because the chassis ground does not work and they won't even turn on without the radio being attached, hence why they ground through the antenna. I'm not saying it's a good thing, just making a point.