Chief Judge Easterbrook swings his trusty cluebat in USA v. Pulungan:
A regulation is published for all to see. People can adjust their conduct to avoid liability. A designation by an unnamed official, using unspecified criteria, that is put in a desk drawer, taken out only for use at a criminal trial, and immune from any evaluation by the judiciary, is the sort of tactic usually associated with totalitarian régimes. Government must operate through public laws and regulations.