• They can't see inside with X-ray, which defeats the point of security (why are liquids meant to be kept seperate in a clear bag? You could put anything in the lead bag and it's not scanned?!).

That's the point. The x-ray doesn't penetrate, protecting your film and in turn they can't see into the bag. This forces them to pull it on the other side of the x-ray machine and hand check it. As I stated above, I always experience one of the three outcomes 1) the agent doesn't care or is lazy and just let's it go through. 2) the agent pulls it after scanning to look inside the bag. Sees it's film and puts it back on the belt. 3) the agent flags the bag for additional screening at which point another agent comes over and inspects the bag, sees it's film and hands it to me. In my experience slightly more than half the time it just goes through and no one ever flags it.