It is nice to know that these security hole exist. Others have pointed out how these might be ... put to use.
I found the article lacking. Here's what I'm missing - nowhere in the article did I gain an understanding of the feasibility of attacking this system. We've elsewhere seen people unlocking cars from the outside (either breaking a window and using the port or wirelessly). Breaking the glass is just that - Break Glass and people would notice.
Having to unplug this device and write new firmware isn't really a hack. Yes - it would be nice if these things had security codes stamped into them for access to the mothership. Still - from outside the car how do I attack this thing? How do I take over this thing and make use of it?
I'm sure there's a way, I'm just not getting a feeling of the priority here. I won't signup for these devices because of the big brother aspect. Shaming the companies for low security is fun. And there are hypothetical attacks on the cell system. But how serious is this? What is my attack surface right now?