When we were still in California my wife was in the back yard and my GSD Gunner was playing/splashing in a plastic baby pool. My neighbor who's a CDC Corrections Officer pops over the fence hearing the racket Gunner was making. Wife calls me at work to tell me Gunner met the neighbor..... Went from playing in the pool flat on the patio to the top of the 6' wood privacy fence ready to rip the face off my neighbor. Luckily the neighbor dropped off the fence into his yard just before Gunner made contact.
Wife said he immediately started apologizing, he thought there was some kind of water leak or something with the noise the dog was making. She said he called 3 more times later that evening to apologize, I missed all the fun since I was on base at work.
That single incident dispelled any doubt I had about Gunner's ability to protect my wife. She turned him into a mama's boy and spoiled him early but he'll protect her if it comes to it. Neighbor never again tried popping his head over the fence. lol