<p>OK, I am back from my trip hiking in the Swiss Alps with a Mamiya 7II and 45 rolls of Fuji 100 Professional 120. The only airport where I was refused a visual inspection on my film was, as I predicted, Heathrow. Since I anticipated this I had the film in a ziplock bag inside a large Domke lead lined pouch. When my gear went through the x-ray machine they couldn't see in it so they pulled it out and asked me what was in it. I told them it was photographic film and they asked to look inside. I, of course, agreed, and they pulled out the ziplock bag with the film in it, looked at it through the bag, said OK and handed it back to me. So, in essence, I got a visual inspection after all. I have seen some talk on these forums that when they can't see inside something they "turn up" the x-ray machine. I have no idea if this is possible but my images do not seem to be in any way compromised so I think the bag was useful. Coming back I was cheerfully granted a visual inspection in Geneva and luckily my return flight was direct to the U.S. so I didn't have to deal with Heathrow again.</p>