My wife and I and mother in law rented out my dad's house a couple years ago. Nice and big beautiful house too. My dad had an alarm system set up for the entire house; garage door, front and back doors, and windows. My mother in law was working nights at the local power plant and my wife and I were sleeping so it was just us home. Around 12:30am, I start hearing the little chime to put in the pass-code when a door or window opens. I pop my head up super fast to hear if my mother in law got off work, which never happened at that time. The chime kept going off and no pass code was entered. All of a sudden the house alarm goes off and the siren is blaring throughout the entire house. I grab my handgun, fully loaded and ready to go. I kept thinking to my self, with adrenaline rushing through me, and scared as shit that tonight was the night somebody might be either held at gun point or worse. I started kicking down every closed door in the house with my gun and flashlight pointed down range. My heart is beating a million mile an hour, my wife is freaking out, and the house alarm continues to blare throughout the house. I finally clear every room in the house, the backyard and the front yard. Nothing. Nobody. Not a soul in sight. No damage or visible break-ins.

Turns out, after multiple tests, the garage door alarm sensors were mismatched from the house shifting over the years. Just one little off alignment and the alarm chime would start going off. Alarm company came out and fixed it right away.