It’s because the ODM these days is programmed to record distance travelled, not wheel revolutions.
Why? Because if you were stuck in snow or mud and spinning your wheels, the ODM would record a greater distance than actually travelled taking miles off your warranty. Same thing when spinning your wheels at a stop light.
The manufacturer established a way to keep it fair for all. Most people never trailer a vehicle so that circumstance is rare and the miles removed are relatively few...but the other circumstances are a lot more common and those miles might add up to a lot more over the warranty life of a vehicle.
For a vehicle manufactured to be used by hundreds of thousands of people across a vast range of conditions, they had to establish a fair average measurement to honor their warranty.[/QUOTE
If the vehicle is NOT being driven The Mileage should NOT increase...