United States v. Madrigal-Valadez, 561 F.3d 370 (4th Cir. Apr. 1, 2009) (reversing conviction for unlawful entry into a military base, for a purpose prohibited by law, in violation of 18 U.S.C. 1382, where the evidence was insufficient to demonstrate that defendant had notice of the requirements for entry before he drove onto the military base access road, or notice that entry by an undocumented alien of a military installation is a crime prohibited by federal law).