As said earlier, if you are in the driver’s seat with the keys, you’re driving, even if the engine is not running.
If someone is sitting in their car in a parking lot and the engine is off, perhaps waiting for their child to get out of school or waiting to pick up their spouse at the train station, then talking on the phone while sitting in a parked, turned off car should be okay.
In the radio story that I heard, the car was running but the car was still parked. In this situation, I can see someone getting into their car in the morning and starting it up to warm up the engine to defrost or defog the windshield, and then make a phone call while sitting in the car.
This person also said that she got a ticket for not properly curbing the tires on her car (turning the wheels towards the curb to prevent a runaway car from rolling down the street). That can be an issue in San Francisco, but she said she got the ticket on a flat street, so there are some pretty aggressive ticket writers out there.
-PJ