> Automobiles are highly regulated and driving is a privilege. There is no _right_ to drive a vehicle from point A to point B, in secret or not.

If we accept your premise that the government can spy on you simply because an activity is regulated, then the Fourth Amendment is effectively dead. Under that logic, the state could mandate interior cameras in every heavily regulated business, or search the backpack of every passenger using public transit without a warrant.

You have a reasonable expectation of privacy for the contents of your trunk, your backpack, and your travel history. The police cannot search your trunk without a warrant just because you are driving on public roads. They should not be able to search your travel history either.

All government regulation still has to be balanced against whether it intrudes or not on the rights of the People. The government can regulate vehicles, including ensuring drivers have met whatever requirements a license might require — nobody is arguing against that. But Flock cameras do not help advance any reasonable state interest in that area; their sole purpose AFAICT is for law enforcement, and in a way that intrudes on any basic expectations of privacy.

Just like cell towers record a cell phone's travel history. Cell phones are highly regulated and having one is a privilege. There is no _right_ to carry a cell phone from point A to point B, in secret or not.

Justifying some control does not justify all control. Voting is a "privilege" too [0] but does that mean any state government should be recording an exact log of your ballot-choices? Surely not.

[0] It should be a far stronger right than what it is right now, but that's separate big debate.