All kinds of weirdo's are knocking on our door these days, some legitimate, many others just checking to see if anyone is home. If no answer they may find it easy to enter and burglarize. If you answer they use various identities like from the water company, the fire department there to inspect some fictitious non-existent problem. They use various reasons to distract you, or to convince you to go into another room to test a water faucet, light fixture, smoke alarm, or in our case to lure us outside and around back with some sort of property line clarification for a fence a neighbor was supposed to be installing. We unknowingly went out back but quickly got wise that the lure was to get us away from the front door so his accomplice could could enter our house while we were distracted. It didn't work this time, thankfully.
I would like a FIOS channel with big loud barking dogs where I, and others alone, seniors, etc. could switch to when anyone knocks on our front door. We could leave the channel on until we crack the door open a bit to identify who the person is. This idea would certainly scare the hell out of anyone knocking and provide a good sense of security for the home owner. I would put an extra speaker close to the door just to amplify the effect.