So think about it this way. For both phones to pick up the sound the volume would have to be a certain level based on a certain distance away from the tv. Even if it was just a coincidence for the same movie to be playing (statistically possible but unlikely), phones tend to ignore background noise under a certain sound bar and distance away. So the fact that both people were also in the same spacing of a tv makes that coincidence smaller, likely sitting next to one another on a couch. Because while TVs have a certain amount of channels in the hundreds, every room, chair, tv distance & volume option is vast which limits it. So coincidences can and do exist, but it’s safe to assume this isn’t one.