He is correct that the forces are different. The equation for centripetal force is Fc = Mv2/R.
Radius is the distance from the focal point, and each seat will be different distances.
So he is technically correct that seat position could be calculated in perfect conditions with accurate measurements.
But none of the data that reaches this service will be remotely accurate or complete enough to make that determination. It will only have one passengers phone data, and even if it collected everyones phone data, phone sensors have a margin of error well above what the difference would be. GPS data is only even marginally accurate up to something like 6ft, and really not even then. Then cars have a lot of other factors like suspension and compression in seats, etc, that would absorb enough of the forces to muddy the data even if accurate sensors were everywhere.
Tl;dr; another cocky person that took a few physics courses but walked away with a poor understanding of real world applications talking out their ass.