Don't be such a pessimist Peregrine!
You just need to use your imagination!
First and foremost, technology is advancing more rapidly all the time so where today's technology is not easily utilized to track the populace, we strive ever closer each day to that point.
Secondly, if the government put a nationwide system in place, much of the tracking hardware could be offloaded from the individual.
For instance, a circuit could easily be designed, similar to the magnetic strip in your credit card or any other verification circuits like those in a car alarm key fob, garage door opener and on and on, etc. Then, the government could set up stations with detection hardware everywhere. The government could further mandate that store owners set up detection stations. Toll booths, street lights,automobiles and all sorts of other key points could be equipped with detection hardware that automatically reads the identification circuit and records time and date and ID along with whatever is 'necessary' for a safe society.
Of course OBD-IV for cars could include mandatory GPS tracking and the identification circuit would be picked up by your car and so not only would your vehicle be tracked, but when you are in it and when you are not could be tracked as well. OBD-IV could also permit law enforcement to shut down your car on command, automatically report you for speeding, driving drunk, failing to use a turn signal and even smoking. What an age we live in!
They have the internet on computers now?
EDITED TO ADD: As a sidenote, I don't think it's fair to compare a parent tracking his children with the government tracking the citizens particularly when the government's existence is only to serve the citizens. While it's true that some people think (mistakenly, in my view) it is the government's role to feed, clothe, educate and otherwise provide for its citizens I find the analogy of parent-child and government-citizen unsettling to say the least. To suggest that I need Dubyah, or Ashcroft or Clinton or any other Fed directing my life in the way that a parent directs a child would be an insult.
(please note that the edited to add portion was not directed at anyone in particular and was added only to clarify that my post adressed solely the issue of the government tracking citizens and that I feel the topic of parents tracking children is a separate issue)