Franchised car dealers already violate this promise; and many (most?, all?) independent service garages and body shops do, too. If you take your car to a dealer for servicing, your mileage is reported to CarFax, which then reports your mileage to your car insurance. If you have an accident and do not report it to your insurance, the accident is reported by the body shop that does the repairs. CarFax pays the dealers, garages, and shops for these data; and insurance companies pay CarFax.
What is worse is that erroneous data are difficult to correct. In advance of an insurance policy renewal, I received an E-mail message asking me to use the insurance company's Web site to report my mileage. When I reported 25,065 miles, the entry was rejected with a message indicating I could not report an odometer reading less than the prior reading. On the Web site, there was a link to view the mileage history for my car. The immediately prior entry was for 241,080 miles, reported by CarFax on the date of the last routine servicing of my car. I checked the invoice for that servicing; it indicated 24,108 miles. A zero had been added to the end of the mileage, either by the dealer's service department or by CarFax! Working with both the service manager at the dealer and the local agent for the automobile insurance company, it took several phone calls over a month to obtain a correction.
See http://www.carfax.com/, which will charge you for a report on a specific car. See also http://www.mycarfax.com/, from which you can get a free report.