We've already got dash cams that record public scenes. Not too crazy to think we might have some sort of body cam at some point (Google Glass for instance). Say there was a bank robbery and the guy gets away in a stolen car. With enough cameras out there, people could piece together where the guy came from and where he went.
I'm big on the right to privacy at home and the 4th amendment, but as I say, have never held that you have a right to privacy when in public.
As far as government becoming too authoritarian; we've got the responsibility to keep them in check.
Anyhow, this reminds me of a Black Mirror episode:
The Entire History of You