Yes, you can autocross an Isetta
Check this cool video with the Isetta autocrossing. I love this because it’s making no sense in my mind, and yet, it makes perfect sense. Look at that little guy out there, little roof flap open for the entire world to see, front paw hanging in the air, narrow little rear wheels skippering it about, refrigerator door acting as what must be an entirely safe piece of racing equipment.