Once I was getting my diaper changed in the disabled loo in the mall and I had absent mindedly not pulled the door handle sufficiently up to lock the door, part way through the door opens and a woman on a electric cart is trying to get in. The door was open long enough for her to take everything in, and people around the door too, me on the change mat, getting wiped. I quickly shouted and an attempted to cover as the door was closed.
I never forget to pull that handle up again, and check it 3 or 4 times before I get changed now.
Thats the only exposed experience I've had. The walk of shame opening that door and leaving was quite anxiety causing, but once we got away from the loo area I quickly forgot it ever happened.