So here's some fun Colombiana for you:
Colombia monitors bank accounts proactively at tax time. Aug to Oct are for '23 taxes, but since the gov't has had low levels of tax participation in recent years, it sent emails today to everyone who had over a certain threshold move through their banks last year, offering a quick path to filing because of the possibility of more taxable income (based on guesses from bank traffic).
Every surveillance state is different, but sometimes in interesting ways!
(I think I might write my surveillance state story for that Strange Horizons call based on financial tracking systems, the way even crypto can be traceable and seized, and the complex tightrope of ethics walked between formal and informal financial economies to bridge issues like central bank bottlenecks for global workers!)