Interesting thread -- especially the surprising number of "nope, not me" responses.
I'll be the first to admit to not having an absolutely perfect record, though I wish I did, and certainly strive to keep it as clean as possible.
But I suspect that if a person hunts long enough, sooner or later it's going to happen to everyone at least once. There's a lot that can go wrong when shooting at game in the field, and if you play the game long enough, sooner or later...
I think it would be very telling if the question had been "have you ever missed an animal?". I suspect that EVERYONE has done that, right? And more than once.
Now, how certain are you that you missed? Over the years, I've found a surprising number of dead or wounded animals that someone else had "missed"... Based on that experience, I've learned to assume that anything that looks like a miss is probably a bad hit. That's not always the case, but it has led me to find and recover animals that many others would give up on.
Food for thought.