I don't think it's fair at all for them to use your credit score to determine insurance rates in any way. What do the two have to do with each other really? If you don't pay your insurance premiums, they'll just not cover you for any of the time during your policy, even if your check bounces weeks after you get "coverage".
I used to work at an insurance agency years ago and I remember a big deal about some idiot who had received a letter from the company saying he wasn't insured because of some problem (he was a high-risk individual and I guess the company decided they didn't want him, even though they told us they would take him at first). The letter was very clear to indicate that he didn't have car insurance at all. So what does he do? Gets in his car, mad as heck, drives down to our office and hits some poor guy on a motorcycle on the way in.
Anyway, I digress. The point is that if you pay your insurance premiums, they have no right to use a credit score to say yes or no to coverage. Some people have rotten credit by no fault of their own, and I think this will just lead to another excuse to charge even more for young drivers (who tend not to have a lot of credit built up).