Most of what you do is already being documented passively. Practically everything leaves a footprint. Your purchases have been tracked since the dawn of time; your bank, paypal, whatever processor you use keeps and stores literally every transaction you make down to the penny. They even send them to you monthly as statements. Bank employees can just go in there and look and the feds *and* state can request those records at will, usually without you actually knowing.
Social security can take a look in there, as can other agencies. Whoever wants to scrutinize your bank will. There is a reason why people who make suspicious purchases get checked up on very quickly. If I go to Walmart and buy a ton of fertilizer and other shit associated with bomb making, that's documented the moment I make the purchase. I can go and spread out my purchases across different stores, and time, but much like the 'In Minecraft' defense, we live in the real world and they're going to notice that immediately too if anyone decides to take a look at your statements.
The government also has the capability to threaten you into producing bank statements and records, generally within an allotted timeframe.
The moment you swipe that Visa, you had a background check done, and there's now a giant fucking transaction right there on your statement for 399$ that's the equivalent of a black kid at a theater going "this nigga just bought a gun!". It'll have the time, date, exact amount, and the location will be logged too alongside purchase codes and other shit, both external to you and viewers and the bank itself.