On the other hand, hunting dogs are smart with long scent memories. My Golden Retriever once allowed the local police to search my entire house without making a peep because our silent alarm had gone off, summoning the police. My husband was on the Plan Commission at the time and had received weekly packets from the city, delivered by a patrolman. My dog had met every policeman on the force and thought it was OK for them to be wandering around the house at 2 AM while we were safely asleep in bed. She just greeted them with a wagging tail and escorted them around until they found us.
That dog never forgot anyone she had met before. She would bark loudly at strangers, but would just wag at them at the second meeting.
Was the alarm that went off at the Van Dams'monitored? If so who responded??
It is not uncommon to "debark" trained attack dogs. This is done through surgical removal of their vocal chords, by someone who has a very unpleasant, nasty streak, and would rather have the dogs CATCH an intruder--who would never hear them coming--than drive him off.