What is the burden of proving a defendant's failure to report to the authorities?

Before reaching the merits, the court notes that the government has the burden of proving appellant's failure to report was willful by a preponderance of the evidence. See Cheek v. United States, 498 U.S. 192, 201-02, 111 S.Ct. 604, 112 L.Ed.2d 617 (1991)(willfulness requires the government prove, in part, that the law imposed a duty and the defendant knew of this duty). The government has not met its burden if the trier of fact credits the defendant's claim of good faith misunderstanding or ignorance of the law. See id. at 202. Contrary to appellant's argument, the government could prevail without presenting additional evidence beyond that of defendant's knowledge.