It is none of that. It is going on here in Philly. It is a way fro robbers to get you to open the door! For about 2 weeks now, off and on, a few nights a week, we have 'kids' at like 2 am 3 am knock on the door and run, then the windows. Our neighbors have had it as well as people on the street behind us. THREE people have gone out to look and got robbed! Load the gun, do not open your door. I guess home invaders have gotten lazy, and want you to open the door for them now.