Just travelled London Stansted to Budapest. Very different experiences at the two ends, though similar result that film went through the machines despite asking for hand inspection.
At Stansted, the atmosphere was crowded, pressured and frantic. The guy overseeing the smooth dispatch of trays through the machines knew nothing about film, and called his supervisor, who was manning the machine scanning actual humans. The supervisor would not leave his post, so we had a shouted dialogue. He said that the rule was that films went through the machine unless they were more than 800. I said "800 what? Do you mean ISO?", and he said "I dunno, whatever it says on the box". This was a problem, because I home-load my film, and furthermore - following the advice of
@koraks - I had taken the (35mm) cassettes out of their tubs and put them together in a well-labelled ziplock bag. But I have a system of colour-coding cassettes, so I pretended the red dots meant >800 ISO (actually Double-X or HP5+) and the blue dots <800 ISO (actually FP4+). So then the red-dot cassettes were taken in the ziplock bag to the other end of the process, where I had to ask several ladies who knew nothing about their existence, or what to do with them when they eventually found them. But they swabbed the outside of the bag meaninglessly, and I passed on. The blue-dot cassettes went through the x-ray machine (as it turned out to be).
At Budapest, security was busy but much calmer. The duty supervisor was called again, but he couldn't have been more polite. He assured me that the machines were older x-ray machines, and that they would have negligible effect on films <1,000 ISO. So all my film went through x-ray machines at least once.
I've just developed two Double-X films that had one trip through the Budapest x-ray machine, and they look absolutely fine.