My Golden/Lab cross Skippy was an excellent guard dog. He loved people and children and cats and other dogs. However, if a stranger came to the house, he always put himself between the stranger and me.
One night a man turned up out of a bad storm. He seemed to be on drugs. He wanted me to take him somewhere, but I refused. He could have pushed past me and gotten in the house. This was soon after my husband died. However, Skippy was between him and me. Skippy was over 70 pounds and he was not smiling! The guy took off after I gave him a towel.
Once, I had to be taken to the hospital by ambulance. My husband said that Skippy placed himself by me and would not allow the rescue squad to take me out of bed. My son-in-law had to lead him out of the room so they could take me to the hospital.
I wonder if it's the Lab in him that gives him that real protective edge? My neighbors have a black lab who is one of the coolest dogs, as well as being one of the toughest dogs (in a good way) I've seen.
They have three kids, all under the age of 9, and we see them all the time in the yard, and he's got his eye on those kids. Most importantly, he's got his eye on anyone who might have their eye on those kids. Nothing gets past him. I talked to the little girl once, she said that their dog never lets anyone in the house (any man, that is) when their father isn't there.
Now this is just speculative, but labs have always struck me as being a little more dominant than Goldens. We always said that if a burglar broke in, Tycho would not only lead them to where our valuables were, he'd make them a sandwich and play a few games of tug of war.