On the contrary, the TV show was inspired by car washes used as drug fronts—not so much money laundering as selling drugs. Cash changes hands, and the attendant gives you a wipe for your dash, but he could just as easily hand you a bag of coke if you'd given him the right amount of cash.
From what I've heard the current way to clean cash is to buy gift cards and then use them to buy items from Amazon/Steam. Sure, the store fronts take a cut but having a 1099 from Valve looks way more legitimate than reporting thousands of dollars of cash.
From what I understand the scheme works like this.
Create a very basic "game" that technically meets Valve's requirements. As long as it runs well enough then it won't be blocked. Have people buy Steam gift cards with cash, then buy the games you have published.
Valve takes 30% and you get a nice check with a verified source of funds from a legitimate company.
Probably way easier and more scalable to setup something offshore than doing a scheme that can literally be thwarted by a guy with a clipboard standing outside
A lot of money laundering involves traceable transactions, no? The point isn't to hide the transaction but rather have a plausible explanation for it that's difficult or impossible to verify. I'd think a larger issue would be that you can't plausibly charge very much per swipe. I'm betting there's much easier ways to launder cash these days with so many digital goods and services with basically arbitrary profit margins than brick-and-mortar storefronts can provide.
Granted, there are benefits to laundering money with literal cash, but you still want some legitimate money trail even if you don't actually hand over the claimed goods or services—enough at least to cover the actual expenses of the business, i'd presume.
Interesting observation. I do use a car wash, not frequently enough as my car is more often dirty than clean, but I have only ever paid cash! For context, I currently live in Austria.