Agreed, its a possibility that the power could be abused, given that the technology becomes pervasive enough - as it sounds like it will. I would hope that the government would give people rights to their privacy in this environment, at least as much as they would or do with your personal computer.
The security of car communication should be a real big concern to everyone. You think hackers getting into your home pc is bad. Imagine a hacker pulling up your location using the 802.11P protocol and finding out your driving pattern. where you leave your car at night. Or if you leave your car running when you go into get your morning doughnut!! You think car theft is bad now!