I once saw a house had a box of candy outside note said please take one. Would be a good way to not have to answer the door.
When I was young (back in the 60's) we went to the county fair once on Halloween. My father did what you described, put a box of candy in front of the door with a sign that said "Please take ONE".
Our neighbor told us that a little girl came by right after we left and emptied the box into her basket, one at a time!