Not exactly a senior moment but close.
On the 4th of July I was packing up to leave the campground. A friend insisted in helping even though I asked him not to. He picked up the wheel chocks after I had the TT hooked to the pickup. We pulled out and left. A couple of days later I remembered that I had hidden a spare set of keys under the chock because I was expecting a friend to get there before me and he needed a way into the TT. At first I thought No problem, someone will just find some random keys and they won't know what they fit. That's when it hit me; the spare keys have a yellow tag on them that came with the TT. The tag has the year, make, model, and length of the TT printed on it. I called the two numbers at the campground, left messages, and sent them a e-mail at 9pm that night. The next day at 8am they called to tell me they had found the keys.
Dodged a bullet on that one.