I have been attacked by a dog and have the scars to prove it.
While on a country road walk with my "new" Hike & Strike another dog came up behind me looking to attack me from behind. I turned and lit up my Hike & Strike but the light and sound didn't scare him, he just kept coming. So, he got jabbed in the face with the ZAP operating. The dog stopped and froze like a statue. I pulled back and backed away. The dog didn't want anymore of what I gave him, so he turned and walked back to his place.
This was no little dog; it was a fully grown blue-nose Pit-Bull.
And yes I almost pooped my pants, but my Hike & Strike prevented that embarrassment.