This is more of an issue of tracibility vs fungibility. The thing that's unique is the bill, not the dollars themselves. Take a stolen $20 bill, deposit it in

This is more of an issue of tracibility vs fungibility. The thing that's unique is the bill, not the dollars themselves. Take a stolen $20 bill, deposit it in your bank account with "clean" money. Now withdraw $20. Is it clean, or stolen? How much is stolen? 100%? Less?