I've lost the front sight off of a 1911. The older sights are pinned and are notorious for breaking off.
I had a guy walk off with my spotting scope. I had a bunch of gear at the range that day and it was getting late. I had to make a couple of trips to the truck. I checked the bench and everything was cleared off of it, but when I got home I realized my spotting scope was gone. I think the guy who did it actually waved at me as I was leaving. Fortunately, it was a cheap scope.