> Do you think Best Buy assigns cash serial numbers to individual products they sold, by default, always?
No but when you took that cash out of an ATM, it logged the serial numbers on the bills it gave you. Then when Best Buy deposited that cash at the bank they again scanned that serial number and can make an assumption that you spent that money at Best Buy.
What that information is used for, who knows? But the flow of cash is definitely logged somewhere, for some reason!
I'd never thought of ATMs scanning the serial numbers of cash, but that makes sense. However, and maybe this isn't leading practice, but stores just seem to put cash in a collective cash drawer, so they can't exactly tell what cash was used for what (though cash purchase would be rare these days). Are there regulations around logging serial numbers now?
Commercial banks don't usually share consumer info with each other. Unless it's the same bank, they're probably safe. Plus, there's no way to obtain a network-connected SIM with cash, so all of this is moot.
How would they even do that? As part of the machine that checks for counterfeit notes? They don't always use that, right?