I can see Govt's getting involved to "regulate" say Poloniex to try to stop this from happening.
I would lay odds that TLAs have all the ingress/egress data for plx right now. It's just a question of whether they want sources & methods hang-out, which strictly depends on the size of the prize. Laundering through plx, or any centralized exchange (or "supernode") is double plus un- clever. Exchanges are for exchange, and do not have holy water.