I did transport lab samples from one place (Canada) to another (LBNL, USA), early 2000s (2002/03? memory fails). Those were samples of some crystals (some ground, some monocrystalline), some man-made and with known ratios of impurities, some not. Some doped with Uranium. Then I did not know the address of the LBNL guest house when crossing the border (hey, I was young and did not know about the added security theatre).
At least they did not look at the sample case (small glass vials, lots of powdered substances, some with "U-doped" written on them) too closely when opening my suitcase...
Biting the hand that feeds IT
