I don't know about the dog but my Chihuahua and my Schnauzer both failed to bark at my son who came very late to pick up his daughter. I was babysitting 2 grand babies and made sure the front door was open so he wouldn't ring the bell and wake up both kids. The dogs were in their kennels in my room and my bedroom door was wide open. Since both babies prefer a very dark room to sleep in I went to my bedroom to watch the football game. Grandson who was spending entire night was asleep in crib in nursery. Granddaughter was asleep in playpen in den. I fell asleep and didn't wake until my hubby got home( he went to game) turning on lights and then both dogs went nuts.He was not quiet in the least.
Let me give you some of the dogs history. Schnauzer is a year old and barks when cats or other dogs are in front yard or when someone is walking their dog and passing the house across the street. Solid door she cannot see through so she is very alert to even know they are there. This dog alerted me last week to two dogs (they were lost and we found owners) on my porch, dogs on porch had made no noise and I opened door expecting to see my daughter bringing over grandson as they were expected and I assumed her barking was to announce they were in driveway.
Schnauzer has never barked at son like she does other family members. Don't know why but she just doesn't bark at him but does jump on him for attention when he gets here. Chihuahua is very young and tiny, she follows her leader, the schnauzer, and barks when her leader barks.
Son says he was able to see with front door open as I had left porch light on, he gathered up daughter, her car seat, and diaper bag. He turned on no lights. He assumed all dogs were outside as outside dogs were barking. His Great Dane (staying here on temp basis) and our hound dog bark at cats, lights, and for sheer enjoyment so I tend to ignore their barking unless it becomes very loud and urgent sounding. He could see I was asleep on bed with door open and didn't want to wake me as it was late. He knew his father was coming back from game and would most likely wake me and I would see granddaughter had been picked up as previously arranged. I asked him if dogs barked and he said no, and stated he heard outside dogs barking and assumed little dogs were out there too because they didn't bark or run to greet him.
Point I'm making here is dogs do not behave the way we expect them to in every situation. Unless you have had your dog professionally trained to act as a guard dog and bark only when they have been trained to, you/ me no one can predict how they will behave in any given situation. While my Schnauzer behaved normally for her, not barking at my son, she didn't behave normally for her by not scratching at kennel to get out and get her petting behind the ears. She greets or insists upon being petted by every person entering my home. Instead of trying to get out of kennel by scratching at door she remained silent and still. My son said he was very quiet and his daughter never woke up. He heard no dog sounds coming from inside the house.
Can't remember the case but it was on a "crime show".
Woman was murdered in own home. Present in home 3 big dogs. 2 dogs were injured so badly they had to be put down. 3rd dog was found in another room that had door closed.
Case was solved-husband did it. What is most interesting here is 3rd dog who survived helped to solve case.
During the attack on wife the dogs started fighting each other, seems that seeing their pack leaders injured and fighting caused them to fight with each other. Since the 3rd surviving dog was owned by husband previous to marriage. The 3rd dog fought the 2 dogs who might defend the wife. Husband bashed the dogs to separate them and isolated the 3rd dog in another room. A dog behaviorist stated dogs never came to wife's defense and tried to attack husband. They only fought each other and took the severe beating he gave them without fighting back. They were able to solve case when a dog psychologist (behaviorist) was brought into the case to examine evidence pertaining to dogs. Other evidence surfaced during investigation that supported the dog behaviorist opinion.
Unless you are a professional dog psychologist we can't really say with any science behind us our musings about the dogs behavior. My own dogs didn't behave the way I expected them to when someone I know and they know came into the house.