I think they did, in our case.
The neighbor’s copper was a huge roll of wire which even we did not know he had.
It was hanging on his wall with his mower bag covering it.
If the thieves had known about *that*, they surely saw the two huge Dobes in my yard.
The neighbor has a dog too but she’s very small and kept in her crate at night.
There’s a couple signs on the fence and house and they all involve meeting your end via gun or dog and I reckon that’s why we were passed by.
Crimes of opportunity such as smash and grabs and easy pickings from open garages are not drastically lower unless the dog is outside with the owner. Home burglaries, esp. while the house is empty, however, are dramatically fewer when dogs are present.
I even read a story about a convict who admitted to being terrified of ANY dog, including when the bark indicated a smaller breed. His excuse, as I recall, was “Them small dogs bite the worst!”
I guess in a way I’d rather be mauled by a mastiff than chewed up by a chihuahua.