While I kind of agree with you, I don't think it is fair to automatically assume that just because an automatic computer system is doing the same thing that a human could do, it can't fundamentally change what that thing means. Things change when something can be done automatically and at great scale.
Take, for instance, license plate scanning. Of course, anyone can see your license plate when you are driving around town, it is public information.
So clearly it is fine if machines scan license plates and keep records of every license plate that crosses a bridge. A team of people could sit on the bridge and do the same thing, so no big deal.
So clearly it is fine if we install the license plate scanners on every street corner in the city, and scan every plate they see.
And it should be totally fine to put that data on a publicly searchable real-time database, so that I can input any license plate number and see immediately where that car is.
These different scenarios might seem like merely matters of degree on the same bit of info, but what it means for us changes immensely as it becomes easier and faster to do it.
I agree that the license plate situation is a concern, but banning the scanners is the wrong fix. I could organize a group of friends to all point cameras out our windows and do the same thing, without the help of government (and in fact, have sort of considered doing so just as experiment, to prove how trivial it would be). The privacy incursion occurs when the government requires you to attach an easily recordable unique public identifier to your vehicle, not when they document sightings of the identifier. Once you put the license plates on the cars, you've lost already -- anybody could be looking, and you'd never know; it'd be basically impossible to regulate.
Not to say I don't think there should be license plates; obviously there's a public safety argument for having them, and that argument has to be counterbalanced against the privacy concerns (and perhaps rebalanced as technologies advance and change the relative difficulty of some kinds of privacy-invading tasks). But focusing on the scanner is pointless. More broadly: acknowledging that people trivially have access to tons of data that, when taken together, damages privacy, and trying to fix the privacy problem by telling them they're not allowed to look at it, is never going to end well. If the problem is solvable at all, it's by controlling access to the data in the first place.
Heh, I figured this would come up, but I think where we disagree is in degree, rather than action.
In your above scenario, I'd start calling for the metaphorical heads of politicians somewhere between "installing scanners on every corner" and "public searchable real time database".
The example we're speaking of here, Facebook has collected the information that the GP poster exists and looks like this. Already publicly and digitally accessible information. Nobody's privacy has been violated by saying that person X exists and looks like Y, nor could that information be used against them. I certainly hope you understand that a live database of car positions is fundamentally different...
On top of that, the genie was unbottled ages ago. You may be able to make some kind of privacy argument re: the plate scanners now, but as the tech advances more and becomes cheaper and it becomes trivial for anyone to do the same thing (I recall an article about someone who set up a scanner in his front yard with some open source toolkits and relatively cheap gear), the arguments that "anyone can do it, except these people, because reasons" start sounding more and more arbitrary and out of touch.
I don't use their services but apparently I'm still tagged in Facebook photos. I never accepted ToS permitting that.