It’s all fine until a neighbors chihuahua gets in the yard and the big dog gets a hold of that intruder
First off the yard is properly fenced.
Second, her dogs are not alone outside, even in their own fenced yard. She always watches them (it’s called being responsible - novel, huh?).
Third, if the neighbor’s dog did manage to get over the fence into her yard (due to location, very highly unlikely), it’s not too likely either of her dogs would do much. They don’t see dogs as intruders in their territory (cats and squirrels are fair game). Strange people is another matter. I should say strange *alone* people. Anyone that comes with a person they already know is liable to be jumped on and begged for attention.