May you could turn off your door bell or post a sign saying "Beware of attack dog" If they do come by say "Could you wait a minute?" Then close the door almost all the way and just "forget" to come back.
Once, when I was little....8 or 9. I was selling Girl Scout Cookies with my friend. I came up to this door and it had a sign that said "We shoot every third Solicitor" I remember thinking "Are we solicitors?" We ended up leaving and going to the next house. When we were walking back by, the owner of the house was outside. He said "Oh, Do you have Girl Scout Cookies?" I said "yes" He asked why we didn't come to their house. We told him because of his sign.....
