Could be a very precocious 3 year old, I suppose...
I once loaned a .20 cal pellet rifle to a guy. He hid it from his very precocious 2 year old daughter, under the bed. He couldn’t find her, and went into the bedroom to look. A pellet slammed into the baseboard, not far from his foot, and he heard laughter under the bed. Why it was loaded and cocked, I couldn’t say....
My Dad kept a loaded shot gun on the floor by the back door after I brought my then three year old over for a visit. I about had a heart attack. I told him to lock up his guns or that was the last time he’d see his grandson. He told me I should “train him better”. I reminded him he was only three and Dad said, “So?” We didn’t visit for a few years... until he locked up his guns.... Sheesh!
Yes, these people exist. And some are relatives who used to be smart.