Well, it's a digital odometer, so I'd say it wouldn't be hard for a professional to hack into the vehicle's system and change the reading. Pero it's not really that important. Check the car's condition if it somewhat "matches" the odometer reading. Drive through differing road and traffic conditions, listen for any unusual sounds, and look at how the owner treats the car. For example, a messy car would most probably indicate a negligent owner.