I left a pinpointer behind once and didn't realize it for a couple of days, I went back to look for it but it was a public spot and it was gone.
Another time I was just walking towards my car at the end of a hunt when my son's daycare called. I leaned my detector up against the car and opened the trunk as I was answering the call. As the daycare told me about my son being sick and needing to be picked up, I took off my belt and pouch, loaded them in the trunk, and drove off to get my son....leaving my detector to fall to the ground as it was leaning up against the car.
I didn't realize this for a couple of hours, when I went back, it was gone. I covered the neighborhood with lost signs and waited...and waited...and waited. Four days later, I got a call from someone who had the machine. They were leaving town for a few days, saw it on the side of the road, and threw it in their trunk thinking it was a "weed-whacker." The good news is, I got it back.