Direct Line 'Drive Plus' Insurance - Use of Data.

Just a quick question regarding how Direct Line use the Data from Black Boxes, as I cannot find a definitive answer on their website.

With other Black Box providers, such as Ingenie, Bell, etc., your driving is monitored on a set basis and the premium changes depending on how well/badly you drive. From what I understand of the text on the Direct Line website, they give you the discount, and the only time they use your data in terms of affecting your premium is when it comes to renewal. They even stipulate that they cannot cancel your policy due to speeding, or send any of such information to the Police.

Surely one could drive terribly, but then not renew with Direct Line, and just reap the reward of the generous discount?

The reason I ask is that I am on a gap year and so won't be renewing for 3 years or so after anyway as I'll be at University, so it would seem a ridiculously good proposition. I won't be speeding or driving dangerously, just occasionally I like to accelerate from lights a little faster than Ingenie and co. would like, but not all the time as I can't stand the drop in fuel economy!