I have this person that his son is friends with mine. every time he comes over to drop off his son (3 times) he just walks into the house, doesn't knock, nothing, just walks in. this last time, I was afraid the dogs would come unglued. why do people do this, have they no manners, common sense, I just don't know. today he is due to bring my son home, I've locked the door so he can't walk in but that's unnerving to have someone just walk in like that even if you are expecting them.