That's a cop-out, fraudsters don't announce themselves so naturally retail businesses look for proxy markers from which to draw inferences. There's an entire money-laundering industry that aims to handle this issue for organized criminals. If you don't engage with this fact than you're just handwaving away the problem, undermining any pro-cash advocacy you engage in.
The real cop-out is that HSBC and friends launder more money for terrorists and human traffickers on a bad day than your typical local racket does in a year, and they only ever receive a token fine and slap on the wrist.
It’s germane in the sense that what you’re arguing against is a rounding error by comparison, consequently, not a material argument against cash-based money laundering in any meaningful sense.
