On the one hand, the only way for the car to function as an extension of the driver's phone is to connect to and intercept transmissions to and from the phone.
On the other hand, this is freaking terrifying.
Given that I will likely one day have to replace my 2006 vehicle with its factory-installed cassette deck and CD player and no bluetooth, I wonder if simply finding and wrapping the car's wifi antenna in tinfoil would be enough to block it phoning home? It goes without saying that my phone will not be connected to it.