but if they did just make the assumption that any odometer reading that was off by 0.62 must have been a km->mi error, couldn't someone attempting to rollback an odometer just always make sure it was rolled back to 0.62 x the number of units driven?
The issue is obviously that the two readings were not taken at the same time, and the technician does not have a field for the unit - just for the value. So let's say he typed in 20,000(in kilometres, so about ~12k miles), then I drove another 5000km, so the next reading taken was 15,000(in miles). So all they could see on their system was my odometer going down by 5000 "units" - it's impossible to work out from this that the mileage was taken in different units each time.
Right - that was my point to the parent who said "it's scary they [Mercedes] didn't figure that out" (that there was a unit change, and thus proceeded down the road of "must have been a rollback"). I was trying to get across that simply making the assumption that mileage going down implies a kilometers-to-miles conversion in reading is ripe for abuse, and so Mercedes would have to assume a rollback first and investigate.
Point taken, but they first could have investigated a unit mixup before assuming fraud. Or they could always track mileage with explicit units, not assuming a default.
