Watched ID channel's Still a Mystery: "Down the Hill". Some things said:
When the video was taken of BG coming towards them, "about 40 feet away", narrator says, "the only way to get to the spot that Libby's Dad was supposed to pick them up was to cross [back over] the narrow bridge". Then Abby's Mom says, "They couldn't pass each other. They were gonna have to wait for him to come to the side before they could go and I don't believe there's any running when it comes to a bridge like that". Later in the program after it being said that police did allow her to hear and see more of the audio and video, Abby's Mom says, "Libby says something like, well the path ends here so we can't go any farther".