Imagine yourself as a heartless criminal....(humor me here)
Now, imagine you have 2 choices.
Break into the home of a couple that hunts deer, ducks, boar etc
Or break into the home of a couple who has no guns and only 1 dog
You're going to choose the easy way out. You wouldn't want to risk yourself on that hunting couple. Both more than likely have a handgun in their nightstands. And you'll surely meet your maker breaking into their home. However, with the couple with no weapons, you can easily quiet them and the dog. Hell maybe the dog is one of those yippe dogs whom is more likely to go run and hide than sit and bark at you or even lunge at you.
It's common sense. Risk your life or not.