Customs departments have a natural interest in those things, because they have two jobs: to raise revenue by collecting taxes from legal imports, and to prevent illegal imports. A lot of illegal imports are goods for which it’s illegal to make a market at all, like narcotic drugs, or elephant ivory. Trading in drugs and ivory are both forbidden by United Nations conventions as well as by domestic laws. But black markets exist in drugs and ivory also, so customs departments have their work cut out for them.
I recently got the link to the video of my talk, which lasts about an hour.