It becomes a pain vs gain problem. How hard do you make it, also balancing the inconvenience.
You could easily force users to enter a one time code via email every 3 months (or more or less time). This would be hard to automate and if you changed it up even more so.
If I get down voted for this commenting against the grain, so be it, but here goes:
I believe that the reason the car companies oppose this is the speed at which it's being pushed. Not that the regulations need to happen.
My understanding is that it takes a car company 3+ years to design / engineer a vehicle to meet the market standards and regulations. It's not an overnight process. So the car companies want this to be delayed to give them time to be in market with vehicles that comply with the new regulations.
It becomes a pain vs gain problem. How hard do you make it, also balancing the inconvenience.
You could easily force users to enter a one time code via email every 3 months (or more or less time). This would be hard to automate and if you changed it up even more so.