Insurance returning unused premium to insured? a good idea.

This article by the Cato institute got me thinking. I have to agree with this article, refunding money not will be bad for the sick since the money not spend on the healthy is used on the care for the sick. I know the law is trying to prevent insurance company from using too much money for administrative cost but hope they set guidelines because insurance companies with more sick people than healthy people might have to limit care to stay afloat.