"If you want to make sure someone is paying their income tax, you don't need to know who the buyer is." Quite the contrary, the way you fight against untaxed m

"If you want to make sure someone is paying their income tax, you don't need to know who the buyer is." Quite the contrary, the way you fight against untaxed money is exactly by monitoring who the buyer is - you fight against the "dark economy" on the edges where it interfaces with the legitimate one, relying on the fact that most of the things one might want to buy come from the legitimate sellers, so you put up limits so that one can't buy anything for large amounts of cash or equivalent without identifying themselves and (indirectly) their sources of income. The gay bar or abortion clinic would be out of scope simply because the amounts spent there are relatively tiny, but for all the large spending (e.g purchasing property, Teslas, etc) the tax verification definitely wants to identify the buyers.