An anecdote I've heard is that some Venusian probe required the import of a large, valuable, (ruby?) instrument window, and customs naturally demanded import duties on what they considered to be a gemstone. So, shortly after liftoff, someone at NASA got to write a letter to US Customs, saying "you know that gem we imported that you valued at $X and we had to pay $Y of duties on? It left the country, permanently. Please return our $Y."
