Probably 50% of what the U.S. Government does is unconstitutional. The government gets away with all sorts of illegal stuff because so many people believe that all the rules, regulations, and laws make our lives better or safer. Every thing congress and the president does has negative effects as well as any positive effects. One example: In the name of public safety we have the TSA, which is nothing more than an expensive nuisance.
These new devices are dangerous because hackers can track your car. Plus, authorities can track you without you knowing it. Imagine this: a friend of yours visits a drug dealer on a regular basis as well as your house. Your friend also has other friends in the business of selling or using drugs. This friend may ride in your car or you in his. If your friend, or anyone he associates with, were to get on the cops radar, guess who else they start following? Do you want the cops tracking you, and subsequently, all your friends? You should see that this may be well intended, but it could drag a lot of innocent people into a big mess, esp. if you're not completely innocent.