Quote:
For air mail this is unlikely (everything is x-rayed), but for some surface mail or containerised freight it would be stupidly easy.

Rio made the interesting decision to use "TNT" as the internal code-name for the product which became the Rio Carbon. That project occupied our attention so much at the time that, to us, it became the primary meaning of the word TNT. This resulted, on at least one occasion, in Rio Santa Clara sending over here to Cambridge a box clearly labelled on its customs declaration "TNT Samples" and containing (what to an X-ray machine would be) small, unidentifiable circuit boards. Customs hadn't even opened it.

Peter