Due process requires that parties receive fair notice before being deprived of property. See Mullane v. Central Hanover Bank & Trust Co., 339 U.S. 306, 314, 70 S.Ct. 652, 657, 94 L.Ed. 865 (1950). The due process clause thus 'prevents ... deference from validating the application of a regulation that fails to give fair warning of the conduct it prohibits or requires.' Gates & Fox Co. v. OSHRC, 790 F.2d 154, 156 (D.C.Cir.1986). In the absence of notice--for example, where the regulation is not sufficiently clear to warn a party about what is expected of it--an agency may not deprive a party of property by imposing civil or criminal liability. Of course, it is in the context of criminal liability that this 'no punishment without notice' rule is most commonly applied. See, e.g., United States v. National Dairy Corp., 372 U.S. 29, 32-33, 83 S.Ct. 594, 598, 9 L.Ed.2d 561 (1963) ('[C]riminal responsibility should not attach where one could not reasonably understand that his contemplated conduct is proscribed.'). But as long ago as 1968, courts recognized this 'fair notice' requirement in the civil administrative context. In Radio Athens, Inc. v. FCC, the court held that ...