This tool allows to interact with other drivers when traveling or maybe used in order to talk to that pushy Audi driver right behind you
Since the attacker's laptop is fully trusted once it has a valid link key, the laptop could be used in order to access all the services offered on the hands-free unit. Often, phonebooks are stored in these units. I am quite certain that there will be more issues with the security of these systems due to the use of standard passkeys.
See the images from the initial Car Whisperer Experiments in the album.
Trifinite Blog
Car Whisperer
