In United States v. Carey, --- F.3d ---, No. 18-10188 (9th Cir. 2019), the Court affirmed the defendant's misdemeanor conviction for BASE jumping in Yosemite.
The Court concluded the permit exception in 36 C.F.R.
§ 2.17(a)(3) – which prohibits delivering or retrieving a
person or object by parachute, helicopter, or other airborne
means – is an affirmative defense for which the defendant,
not the government, bore the burden of proof.
Of note is the extended discussion on this issue. If you have a case where it is unclear whether you are dealing with an element or affirmative defense, this decision is a good place to start.
The Court also concluded the magistrate judge did not need to recuse himself despite reading an article about the case.