If you look carefully at their videos, you'll notice that each one of their vehicles is followed by a dark Prius with two people in it, and some videos (others

If you look carefully at their videos, you'll notice that each one of their vehicles is followed by a dark Prius with two people in it, and some videos (others are shot in angles that one cannot be sure) show another dark Prius driving in front of their vehicle. They've launched a PR stunt, not an unmanned delivery service.