Comment by wolvoleo

The same way you avoid it doing anything else illegal that involves cash.

Crime is risky, but not pure anarchy. It is still based on trust and rules, just not those written in the law.

There are plenty of regular people who interact with criminals, for example drug dealers, without getting murdered or robbed of all the cash they are carrying.

In Argentina, years ago, you could exchange dollars/euros for pesos on the street and get a far better exchange rate than in a bank. It was obviously aimed at tourists, who didn't get robbed, or the whole enterprise would stop.