When I visited Istanbul, I passed through a district with an endless number of exchange shops, and it seemed like a place where you could easily wash money without any bank account involved. I believe Turkey isn't alone in having such a culture of buying/selling US dollars by tracking the USD rate.

Do the IRS and say Turkey's tax office tracks these as well? Assuming that you don't try to deposit the exchanged for bills in a bank.

Couldn't someone offer Bitcoin exchange in existing currency shops or the same service via Bitcoin ATMs? How would the IRS and its equivalents track that without requiring identification and registration before use? I suppose a small amount would be allowed for the tourist aspect but then you could use a group of friends or employees to wash small amounts. If you require ID for that, including tourists, then you can track it.