I would suggest that it is somewhat beyond the scope of a simple over-stressing structural failure though.
I would agree here - merely pointing out that there had been at least one accident that went against your statement
there has never been a failure for the structure due to flight loading,
There was no suggestion though that the tail was not airworthy to start with, Aerobating a non Aerobatic aircraft though is asking the aircraft to put up with loads it was not designed for.