This technology is really awesome, but I have to admit that I am scared to death of anything that can find me by my heartbeat under 6 feet of building rubble. The first thing that came to mind were those robotic octopi from The Matrix.
You could probably come up with some sort of regimen that would have people coming or leaving the house such that the number of people in it always stayed below what was indicated on the census, but it would still be a major concern.
Related are sentences that are grammatically correct, but semantically nonsense: http://en.wikipedia.org/wiki/Colorless_green_ideas_sleep_fur...
This isn't meant personally; you see this "Dystopia ex Technology" in Hollywood movies and popular novels. For every "Pacific Rim" we have, there's several "Matrix" clones ready to tear down our confidence in machines.
According to people who know better, you misspelled the word "FUD".
You could argue that the robots symbolized governments and Zion the freedom-seeking people. But that symbolism would be much more apparent in a different story, like Firefly/Serenity.
The reason that people have a negative reaction to technologies that can be used for spying is that right now, in real life, spies are committing crimes against citizens using virtually every technical facet of modern society.
Guns are technology which can directly kill me, but I'm not too worried about guns, or even must gun owners. But when you're talking about a technology that (due to massive cost) is only available to governments with questionable oversight, that gets worrying.
In this specific case, I'm not particularly concerned - but you can see how the availability of the tech in question matters. If only people who are already more powerful than me can have it, it's much more likely that its power can be (ab)used to my detriment.
It's going to get harder and harder to reassure delusional people that their delusions are false when they become technologically feasible.