It's also impossible. "I'm going to kill some soldiers when I get back" might refer to my super secret terror plot, or my PlayStation-related plans for the evening.
Here's my solution to that. Gather all the information possible, including things you've purchased so that I know whether or not you actually have those games or any of your friends do (and whether you actually play them). Assess, whether any major life changes have occurred for you based on all my data-mining and algos and assign a risk-factor for that particular statement. Monitor/filter your subsequent (or even previous?) communications (SMS, calls) for anything that might increase the risk-factor. If it's above a certain threshold, dispatch a discrete drone to follow you around 'just to be sure' (it's ok, you won't even know it's there). Maybe one day, I might decide to have armed drones, you know, 'just in case'. Oh, and make all of this automated because software is eating the world and what not (bugs? what bugs?).
Obviously, I say all of the above tongue-in-cheek but it wouldn't surprise me if there are people in government (or the security services) who actually think that way.
There very definitely are people who think that way who make policy decisions - most of them. They see themselves as invulnerable demagogues, and their apparatuses as being able to do anything, because they say they can. Computers are this amazing thing you can wave a wand at and anything can happen, and because it came out of a computer, you know it's GOT to be right.
We used to have a saying for this, which was "high on their own bullshit".
Career politicians are just that - in politics, for their career. Not for your sake. Not because they want to change things. Because they see a trough, and daddy stuck his nose in it and did alright, so why can't I too? This doesn't require any particular knowledge of the world around you, or empathy, just a machiavellian drive to clamber on corpses until you reach the top, where you can crown yourself king of the ashes.
The NSA is building a whole installation in the Western US specifically so they can do exactly what you propose, or as close as they can get at this time.
Obviously, I say all of the above tongue-in-cheek but it wouldn't surprise me if there are people in government (or the security services) who actually think that way.