And when they check your cars mileage and it has a boatload more than your phone recorded? After you signed something that agrees you'll always (or almost always) have your phone with you?
If they track the phone, how can they tell if you are driving or just a passenger?
My TomTom 5000 SatNav, which I bought for like $200 has a permanent connection to the internet in all countries of the world with no monthly fee. It has an integrated SIM card and TomTom just paid some fee so that it can connect to the internet and get traffic updates wherever I am in the world. An even cheaper Kindle 3G also had that. So I guess it must be relatively cheap.
Joke's on them, the per-vehicle mileage goes down every time they ask.