I'm posting this link [1] to the Forbes article (Hackers Reveal Nasty New Car Attacks) the second time today, but it is also relevant here.
[1] - http://www.forbes.com/sites/andygreenberg/2013/07/24/hackers...
[1] - http://www.forbes.com/sites/andygreenberg/2013/07/24/hackers...
A rather large assumption on your part, no?