I had a guy here all morning installing a new line for DirecTV, so that my daughter's TV could get satellite. The dogs (who were out in the back yard) correctly announced his arrival with a loud fanfare of barking, and barked once or twice more when he walked from the house back to his truck. After that, they were quiet-- they'd already announced his presence, and didn't feel the need to keep yelping about it.
Later, he went out for a while and stood on a ladder, just outside the invisible fence line, and when I went out to see how it was going, they were sitting there, quietly observing him. I then walked through the back yard with him, and the dogs both made a friendly leap at him (they still really, really want to leap on people to greet them), but when I told them NO! OFF! they dropped back to the ground and politely escorted us through the back yard.
In short, they behaved like good doggies:-).