From a US Customs Service pamphlet:

Certain articles considered injurious or detrimental to the general welfare of the United States are prohibited from entry by law. Among these are absinthe, liquor filled candy ... lottery tickets ... seditious and treasonable materials, ... and switchblade knives (however, a one-armed person may import a switchblade for personal use.)

Later there is a section on "Piratical" copies of copyright material.

update 2005... this followed a writeup that matched the node title. now it is gone. if only the administration paid attention to continuity. ah well.