Are you aware that if you give false answers on your health or life insurance forms that you can legally be denied benefits? The doomsday scenario you paint has been in effect for the past 30 years. Ain't nobody died as a result.
I had to be blood tested for my last life insurance policy. I guess this way the insurance company can determine whether I have given truthful answers. It also helps if you are LESS prone to certain illnesses, giving reason for reduction in premiums. Those who do not commit crimes are protected by the same DNA samples that convict others.