Central authorities already distinguish cash transactions with illegitimate intent (e.g. for smuggling or money laundering) and legitimate cash transactions. It

Central authorities already distinguish cash transactions with illegitimate intent (e.g. for smuggling or money laundering) and legitimate cash transactions. It's not a big stretch to think of tumbling being treated as a form of money laundering, where the nature of the transaction may be wholly legitimate, but the criminality is based on the intent of the transaction.