In the US, you will have the right to request hand inspection of your film no matter what the film speed is. They may try and talk you out of it if you have less than 800 speed, but they still have to honor your request.
The tricky part is going to be in Europe. They have no such rule about hand inspecting anything at all and likely will make you run your film through the machine. I have used the lead bag before on foreign trips. Just make sure that you do not put the film in checked luggage. Most of the checkpoints for scanning carry-ons do not have x-ray levels high enough to ruin your film on a couple of passes. One thing though--damage to undeveloped film by x-rays is cumulative. This is what the guys at security checkpoints never tell you. So, if you travel through a lot of airports, museums, or landmarks that have x-ray machines all on one trip, it could at some point add up and possibly fog your film. In those cases, I would recommend either periodically developing your film during the trip or simply buy film there when you need to.
Again, if your film gets scanned no more than a couple of times on your return trip, I would not worry about it.