Off topic, but this story reminded me of a little experiment performed a few years ago by a wacky Japanese TV show. They got a bear suit. They even left it in the bear cage at the zoo so it would smell like a bear. They arranged with dog owners to have the guy in the bear suit attack them while they walked their dogs in the park to see what their dogs would do. A few of the dogs attacked the bear (the suit was padded), but almost all of the dogs ran away. Nearly every owner said their dog would protect them, and most of them took off. Wish I had video for you guys.
And yes, by Western standards this is a cruel trick to play on a dog. Owning dogs in Japan has only gotten popular in the last decade or so, so in general there isn't the same level of empathy.