It's not terribly uncommon for burglars to knock to determine if anyone is home and if they get no answer, to attempt entry.
Fine. Since I'm one of those "paranoids" that carries 24/7, I'd rather one attempt entry while I'm home than when I'm not. I'd rather stop a burglary in process than pick up what's left of my home later. I can see the front door from the family room, but it's about 40 feet away from me. And I can see from there who just came up the porch steps. Some open floor plans are great for that. Driveway alarms are great too. So are security systems with cameras. But nothing beats nosy neighbors. Neighborhood watches are best.