United States Homeland Security Investigations (HSI) of U.S. Immigration and Customs Enforcement agent signs affidavit for Warrant against Mt Gox, worlds largest bitcoin exchange. Mt Gox's U.S. bank account seized.

I wonder if Mt. Gox were trading in lawful money, instead of Federal Reserve Notes, what would be the outcome.

The U.S. bank account I use that is linked to Mt. Gox has demand for lawful money verbiage on the signature card.

Seizure Warrant here.