I remember replacing the worm gear on my odometer and wondering how many miles were "lost" from it while it wasn't turning during those 6 months or so that I was getting around to the project.
Not that I'm advocating a Orwellian tracking system be installed. Just saying I can see how existing systems could be argued against.
All you need to do is require people to report their odometer reading when they renew their vehicle registration, and have huge penalties for willful mis-reporting. Traffic stops and service records at tire shops, oil change places, etc. provide plenty of evidence to prosecute someone, and if the penalties are severe enough, the threat of enforcement will be enough to keep most people honest.
Not all states require periodic inspections. Who will be checking those odometers? Is it the honor system or are we requiring a third party inspection?
In Oregon, there are two metro areas (Portland and Medford) where vehicles must be tested because of air pollution concerns. If you have a pre-2005 vehicle, I'm pretty sure they still use a measuring device to see how many pollutants your car generates. For model year 2005 and later, they hook their computer to your car's OBDII port and ask the car's computer how it's feeling. If the computer says "fine", they pass you and you can renew your registration.
Comparatively recently, they let mechanics and quick change oil places do the test for 2005 and later cars, giving them the option of charging a fee for it.
Oregon doesn't have vehicle safety inspections but it doesn't seem unreasonable that I could go to the official DEQ or DMV locations if I wanted to have my mileage inspected or maybe pay Jiffy Lube a bit extra because they're closer and their hours are more convenient.
The issue with that is that, though, is the same problem with taxes: many (most?) people aren't going to want to come up with the money to pay their mileage bill on the spot. There don't seem to be great answers for that.
Oregon has a pilot program where they put a device in your car and charge your credit card 1.9 cents per mile. https://www.myorego.org I'm sure that's what they'd like to have people do but I don't know how many people want to do that.
They should require periodic inspections. Too many vehicles here are too dangerous for public roads, and having bald tires, no brakes, and rusted out suspension just makes them worse.
Not that I'm advocating a Orwellian tracking system be installed. Just saying I can see how existing systems could be argued against.