> With their current approach they will almost certainly get traced eventually and end up in jail.

Depends. If they are a couple guys (or a single guy), and it's a one shot for him, he has very good odds of getting away with it. Cleanly launder his BTC and then move somewhere not suspicious and keep a low profile. At the end of the day, $4m is not that much money (ie: not able to afford multiple Ferraris).