Does this mean for this "hack" to work that you need to be in the car AND have the key? Or do you just need to be in the car hack the touchscreen and you can drive the car? To me, it sounds like you need to be in the car and have the key. If that is the case, then can't you just drive the car away and don't need a "hack"? If that's not the case and you don't need the key, then why this talk about stopping the car when it's going slowly? Why not just drive away, who cares if you can stop it from rolling? I don't get what this "hack" actually does. A thief breaks into your car, accesses the Ethernet port/CAN bus then makes everything go dark? Why not just use a hammer and smash the screen? Pop the frunk and disable the 12V battery? Like I said I don't get it.
EDIT: Actually I should say I know it's a design flaw, but calling it a "hack" is a little much, imo. I know it needs to be fixed, but the word "hack" is a bit much. As a developer will tell you this is a "feature".