Many people wonder why the VLES GO-bag has a full role of duct tape in it. Well, for one thing, duct tape can hold together almost anything, including hems, fencing (we've experienced this), torn bags, etc. But, it also can save your life.
None of us wants to think about this but, in the event of a nuclear incident, we will need to get into a building, shut down any air conditioning or other air intakes into the building and then duct tape around openings (windows, doors, etc.) to prevent contaminated air from entering. Duct tape can literally help to save your life.