>it's unusual that a presumably trained dog at a show would bite someone<
That it is. In this case, the dog was not entered, because it was a rescue there to see if it had "aggressive" tendencies. It attacked the woman, when she tried to keep it from killing her dog (the Akita originally attacked her dog). She put her foot between the 2, and the Akita darn near tore it off.
This attack is all over the show dog lists. This is NO showdog, it's a vicious dog someone turned into rescue, and some do-gooder was trying to rehabilitate it.
Oh my. Thanks for the update.