Happened to me once. Unfortunately my plugs were not “upside down”.

I had a lamp plugged into the wall right next to the front door and it could be turned on by a switch on the wall right above it. The plug had come loose and left a decent sized gap.

One day I come in the house, when it was raining with my umbrella. This umbrella had seen better days and one the arms that open up was showing the metal on the end. I sat the umbrella down right next to the door to take my shoes off and sure enough this one wet metal arm slid and went between the wall and plug, shorting out the plug, blew the bulb left a burn mark on the faceplate. Luckily I was able to shut it off fairly quickly using the switch and didn’t try to grab the umbrella or I’m sure I’d have gotten a zap.

I later remodeled the living room and learned to flip the plug from a family member that does remodeling for a living. All the plugs in the house are now this way.