You would be surprised at how often stuff like that happens. A number of years ago when i worked at the Dive unit in Shearwater, our EOD team received a call about an explosive at someones house. It turned out to be an old hand granade. It was sitting on this old guys mantle for years and years. He had grandkids and stuff in his house all the time. As well when they were dredging out Bedford basin around 1999 or 2000 they pulled up a 500 lb bomb whose outer casing had rested competly away. All that was left was the explosive. They had to ship that one to Gagetown because there is no where in NS to detonate anything that large. The diving units on both coasts get calls like this on a regular basis. Amazing when you think what people keep as a "souvenir"