Back in the late 1950s and early 60s, we lived in a tract house in Whittier (East of Los Angeles, California). It had a long driveway partially screen by tall (about 5 feet) Juniper bushes. But, from my bedroom window, you could clearly see down the length of the driveway and much of the street.
My dad ran a pair of wires to the last bush that bordered the sidewalk and embedded a speaker well into the concealed heart. During the evening, he would sit in the darkened bedroom and speak to the approaching kids. Nothing scary or ominous, just "Hello, [fill in the name]." Except for a Jack-O-Lantern we normally didn't have any "scary" decorations. Still, it was surprising how many would freak out. (Mind you, this was before color TV, about the same time transistor radios came out and the United States still couldn't reliably put a satellite into orbit.)
How did he know what names to say? Well, he knew most of the kids in the neighborhood, along with the relative sizes of their siblings. He just identified the parent with them and, even with low light levels and the costumes, he had a pretty good idea who he was talking to.
For those who were upset, most of the moms were able to talk them past the disembodied voice to get their candy.
I didn't see too much of it. I was out trick-or-treating myself.
Of course, since the mid-60s, kids have been too tech savvy to be frightened by a little bit of quiet, disembodied audio.