In Kalifornia, we have FasTrak, and if you don't have the transponder they just pay it off your plate, since they take a picture of every car that goes through. Your plate has to be registered, though, for it to work. No speed limit in the toll traps, though. I've been through the traps at 80+ without issue.
As for tracking your movements, the Gov doesn't need cameras or transponders. We all have cell phones, and they are all GPS enabled at this point (even if you think you have turned it off). They know everything we do, and hear everything we say. Also, CHP is now installing that license plate scanning software that looks at every single plate that comes into the field of view for the cop car and looks for whatever violations or warrants it can find. It is so pervasive that it just becomes part of the background noise. It falls into the "There's nothing I can do about it, so I don't waste time worrying about it" category.
If they REALLY wanted to keep people from speeding (at least out here), it would be easy enough to track people and send tickets in the mail. People would slow down soon enough. But that would be a BIG hit to the General Fund, so it would die a quick death. I call tickets Voluntary Road Tax. You don't want a ticket? Don't break the traffic laws.