I don’t know specifically about Far-IR based imaging, but visible spectrum imaging already has this:
Basically, it’s live footage, 24/7 from high altitude planes. They’ve already deployed it in at least one US city without asking the public first.
This kind of tech can literally see everything that goes on outside of buildings at all times for an entire city. If there’s a breach, it’d be trivial for you to figure out where everyone in the city lived, just by tracking them and their vehicles.
Originally the tech was developed during the US’s wars in the middle east. The application was, as soon as a roadside bomb went off, they could track back in time to the last vehicle at the bomb’s position, then track forward to see where the bombers went, then command sends a unit to get some kills on the board.
