> The biggest problem with them, by far, is how do you collect this mile information? In the UK every car is required to have an MOT done, which is an annual,

> The biggest problem with them, by far, is how do you collect this mile information? In the UK every car is required to have an MOT done, which is an annual, comprehensive, safety check of the vehicle. The results are recorded with the Ministry of Transport. It would likely be very trivial to add odometer reading to the recorded data (it probably is recorded already, for that matter), and use that.