I have 2 pits at my house. They, like Cope said, are my babies. I had to put one down last spring for serious health reasons. Cash is a year old soon, and Moxy is only 3 months old. They might as well be my offspring the way they live in my house, or maybe I live in theirs....

Anyways, my dogs are very laid back when I am around. They get a sense that if I am Ok with someone being on the property, they aren't going to act different. On the other hand, there has been a few instances of unwanted guests while I
was home where they quickly escorted someone to their vehicle to leave. They are a good persuader.
When I am at work, or out of town, with my wife and kids home however, it is difficult for friends or family members that do not come over very often to get into the house. The dogs love my wife and kids, but they know that I am the man of the house, and they are very cautious who they allow to come in when I am not home. My mother and father, my uncle, and my brother all call before they come over to make sure I am home. If I am not home, they usually wait to come over. Some people might think that is not a good thing, but it really works rather well for me.
They would never harm any of my family, no matter what. I have seen my daughter grabbing their ears, twisting and pulling in a painful way. ( I do not LET her do this, she is learning) The dogs just yelp a little and walk away. they NEVER nip or growl in an aggressive manner towards any of us. When I am home, I have many friends and family over to the house, and everyone loves our dogs. They are very playful, and quite entertaining sometimes to watch them play.
My point is, anyone who intended to cause harm to my family would be sorry if they tried to gain entry to my house. My dogs
would stop anyone who was trying to get into my house unwelcome. The only scenario that someone would be able "get around" my dogs, as someone might put it, Is to shoot them through a window. In that situation, you have just alerted me, and you have only 15-20 seconds to get several miles away. Any man who kills my dogs would not be able to hide for long.