Almost every modern kitchen today is equipped with a microwave oven, mainly because microwave ovens offer a fast and convenient way of cooking and reheating food. Indeed, it has become a standard appliance in most households. Studies have shown, however, that microwave ovens are not completely safe and their use has occasionally resulted in serious injury. Because of this, some consumer advocates argue that microwave ovens should not be so readily accepted as a standard appliance until they can be certified to be completely safe.
Which of the following, if true, would most strengthen the argument of the consumer advocates?