The lead plaintiff in the case, Nyree Hinton, bought a used Model Y with less than 37,000 miles (59,546 km) on the odometer. Within six months, it had pushed past the 50,000-mile (80,467 km) mark, at which point the car’s bumper-to-bumper warranty expired. (Like virtually all EVs, Tesla powertrains have a separate warranty that lasts much longer.)
For this six-month period, Hinton says his Model Y odometer gained 13,228 miles (21,288 km). By comparison, averages of his three previous vehicles showed that with the same commute, he was only driving 6,086 miles (9,794 km) per 6 months.
Edit: I just want to point out that I just learned that changing your tires to ones of a different diameter can also affect how your spedometer clocks. So yeah, this issue is full of nuance and plausible things as to why this could not be true.
Maybe location tracking from Google maps giving a date when the car was driven and where, with a simple excel of distances calculated and tallied up for a given month or two.
If the owner had a photo of the dash with the distance reported a few months earlier start there to see if the report distance matches what the excel table totals up.