i'm sure they already think its a bad idea but thats exactely the problem, if there were a car drivers forum the members could be as high as 1 million. 1 million people paying for a small % (10,000 people) of its members will have a low premium but 10,000 people paying for a high % (5000 people) of its members will have a high premium. its how many people that are contributing to the cost determines how much each person pays.
if there were half as many people paying income tax then the govt would need to take more to cover the same costs of the population.