I've wondered about that. In the state of the US where I live (Colorado), we have a point system (not all states do). Furthermore, in some states it's legal to base insureance rates off of five years of tickets, and in others (like Colorado) insurance companies are only allowed to see the last three years of data (as I understand it).
So even though I had some tickets four years ago, when I've been calling around for quotes I sometimes answer "no" when they ask if I've had any tickets in the last five - after all, they are only allowed to know the last three years of data!! I'm still not sure if it's a good idea, so sometimes I do tell them about the tickets figuring that if I ever was in an accident they might be able to claim my not telling them about the tickets voided the policy.