Brazil instituted a cash-back system where any receipt that is created you can opt into putting your name/ID on it tying it to your person, even for cash transactions. You get around 0.5% cash-back if you do.

This is still important even for non-cash transactions because Brazil has quite strict financial secrecy laws (ie law enforcement can't see into your bank account without a warrant). So you have to opt-into giving the government this data.

I am not sure if it is good for money laundering (I assume it helps), but it massively reduced tax avoidance.