I think the shenanigans referred to are on the part of the merchant (not reporting income, stealing from the till or enabling bribes) rather than the consumer (card fraud, etc.)
> "The estimated amount of money laundered globally in one year is 2 - 5% of global GDP, or $800 billion - $2 trillion in current US dollars. Though the margin between those figures is huge, even the lower estimate underlines the seriousness of the problem governments have pledged to address."
I meant source for "a lot of this happens through shops that use anonymous cash transactions".
$2 trillion in $10 bodega transactions is 200 billion bodega transactions. Something tells me it's not the silver in the till that's the main problem. Or even the notes.