Interesting, the FCO has put out traveller advisories across the Balkans advising travellers of stiff penalties for unauthorized substances, and noting that airports have machines of extraordinary sensitivity. I never touch the stuff, but I had an interesting experience in London a few years ago. It's a little-known fact that you can take an outside path between the two terminals, instead of the monorail. I took the meadow path, as it was a beautiful day, and I didn't want to miss the chance to walk on English soil. As it turns out, it was also the de facto break area for the airport employees, who were smoking a peace pipe or two near the path. After just walking past them, I got a dismissive sneer from the elderly lady using the electronic wand to sweep the luggage in the second terminal. But I did get a buttercup out of it, so still a win over the monorail.
