A case decided on April 11, (United States v. Uddin), held that a person may be prosecuted for operating an illegal money transmitting business under 18 U.S.C. 1960 where the government shows that the person operated a money transmitting business knew the business was not registered with FinCEN.
According to FinCEN:
The judge rejected the defense argument that the government also must show that the person operating the money transmitting business knew that the business had to be registered, thereby following the general rule that ignorance of the law is no defense. This case illustrates that money services businesses are responsible for knowing their registration obligations under the Bank Secrecy Act and implementing rules.
See: http://www.fincen.gov/rosenopinion1960.pdf for a copy of the Opinion.