X-ray machines can and do fog film, especially after repeated passes. If your journey takes you through several airports, the levels of exposure may build up enough to damage the film. I have only seen it happen a handful of times, but it can happen. In the United States, regulations give you the right to refuse X-ray and have your film checked by hand. Outside the United States, it's between you and the guy with the submachine gun.
Discretion is the better part of valor.
Plan what equipment you will need to make memorable photographs of your trip. Don't take everything you own because you won't want to carry it. If you are taking a video camera, figure it into your plan. Ideally, one person should do the video while another does the still photography. It's surprisingly difficult to do both well and still enjoy yourself.