Is there a defense to a prosecution for failing to report for a preinduction physical examination?

Appellant contends that a prima facie showing that his I-A classification was without basis in fact is a defense to a prosecution for failing to report for a preinduction physical examination. The law is to the contrary. In United States v. Heinrich, 470 F.2d 238 (9th Cir. 1972), the court, sitting en banc, held that a prima facie showing by a registrant that he is entitled to a classification other than I-A does not relieve him of the duty to report for a physical examination ordered pursuant to the existing I-A classification.