The problem with your example is that the law doesn't necessarily have a hard definition of driving and that is where the judge will have to use discretion (AKA use common sense in the context of the situation to find if the person was "driving").
Just some googling found the following article on California's law in relation to the definition of driver/drive. California law defines "driver", but does not define "drive". Thus the law does not require the judge to find a hard definition of driving, but rather to see the specific situation.
The first case example shows that circumstantial evidence is enough to establish someone as a driver (example raised was a single person in the driver's seat with the engine running and the car parked on a freeway 1 mile from on-ramp).
https://www.justia.com/criminal/docs/calcrim/2100/2241.html
Definition of driver in the law in section 305, but no subsequent definition of "drive":
https://www.dmv.ca.gov/portal/dmv/detail/pubs/vctop/vc/d1/305
The texting law in California uses "driving" in phrasing.
https://www.dmv.ca.gov/portal/dmv/detail/pubs/vctop/vc/d11/c12/a1/23123_5
I think if the lawyer was trying the same shenanigan in California, the judge would find that he fits a common sense definition of being the driver.
Anyways, if the lawyer was trying to test the law and whether the definition of "driver" or "driving" vs "operator" has a distinction, Minnesota was not a good state to pick, as the relevant law says:
"No person may
operate a motor vehicle while using a wireless communications device to compose, read, or send an electronic message, when the vehicle is in motion or a part of traffic."
https://www.revisor.leg.state.mn.us/statutes/?id=169.475