Professor Clemens: Many people die in traffic accidents each year  Since airbags can prevent deaths in traffic accidents, motor vehicles should be equipped with airbags  Professor Sanford: Your recommendation is useless
It is true that airbags may save some lives in traffic accidents, but seatbelts can prevent far more deaths each year than can airbags
does not show that the benefits that would follow from Professor Clemens's recommendation would be offset by any disadvantages