Perhaps one can paint a QR code and sell it as art. Can you still do it by selling just the coins with no XBT value on them at all?
Key definition is following:
The term “money transmitting service” includes accepting currency or funds denominated in the currency of any country and transmitting the currency or funds, or the value of the currency or funds, by any means through a financial agency or institution, a Federal reserve bank or other facility of the Board of Governors of the Federal Reserve System, or an electronic funds transfer network.
Laws that are important for compliance are:
31 USC § 5330 - Registration of money transmitting businesses.
18 USC § 1960 - Prohibition of unlicensed money transmitting businesses.
They are short and easy to read.