That's a shame. Even accidents can have lasting effects.
That also brings up a good point (although it did not happen in the above example), the dog or the owner for that matter is not always solely responsible for some of these incidents.
Many times children can cause these kinds of attacks, not that they intend too of course! by that I mean that maybe the kids pull too hard on their (dog's) ears, tail etc. I realize that you would hope that your dog would be oblivious of these types of things, but maybe not always. I just watch 'em like a hawk when kids are around. I don't want to be responsible for something like that.