I don't have an alarm, but I do have a particularly noisy beagle. If he goes off at night and I haven't heard any suspicious noises, I investigate, armed, while my wife prepares to call 911 on the old cell phone we keep in the bedroom for emergencies. He's usually upset that a skunk is using our backyard to get from one place to another, but you never know. If I'm really concerned, we'd stay in the bedroom and call 911 for help, but I can't call the cops every time he barks or we'd have a patrol car in the driveway 24-7.
"The gun has been called the great equalizer ... It insures that the people are the equal of their government whenever that government forgets that it is servant and not master of the governed." --Ronald Reagan