Pitbulls do not block family pathing. I've seen people put a small army of dogs between their family, and any would be intruder.
I try to put my family so far away that it takes a long time for them to reach the door, hoping that the burglar will have moved on... sometimes they'll kill the wife and kids for no reason. I never do, personally, even if it would be worth an awful lot of money. In a way I see this as a 'lite' version of the moral dilemma presented in Day Z. A world with no rules, you can kill people or aid them. It's harder to be a nice guy in a nasty world, than a nasty guy in a nice one, and there in we start to see the differences in people. It's an amusing commentary on how people act when there are no real consequences beyond the nebulous concepts of 'being nice' and 'being mean'
I don't feel that losing your family should be the end of the game, or else murdering someone's family is a good troll tactic-and no amount of cunning traps could stop them getting to the exit, so anyone committed to the path of dickery could just dance on the porch waiting for the family to show up, murder them, then leave, knowing they've just ended that person's game.
Some people are particularly mercenary, and will be glad when their family is gone as they can make their home even more deadly. Others make a big deal out of trying to protect their loved ones. In my most recent home (a few episodes ahead of my upload, it'll be available eventually on my channel), my wife was killed for no gain, the robber did it then moved on (again). I built a tomb of stone and steel around her corpse, as a lasting monument to my grief... a fitting resting place for the wife of a dwarf!