Lutz, I think the logic is that as there is no towball fitted the vehicle is incapable of towing anything and therefore can't be tested as a towing vehicle. However, if the bracket was found to be in such a poor state that it is likely to fall off solo then a failure would be recorded as it would with any other insecure bodywork etc.If that is the case, it makes a complete mockery of any requirement concerning towbar testing.
Yes, but the likelihood of the bracket and its attachment to the car being a safety hazard is so much greater than the (detachable) towball. If the towball was OK to start with, then it's highly unlikely that it would become loose during the life of the vehicle.If that is the case, it makes a complete mockery of any requirement concerning towbar testing.