I probably would have spotted them, having had experience with similar devices, but the average hiker probably wouldn't have. They should have far more serious charges leveled at them. Out here the pot farmers hang fish hooks at eye level in trees to help discourage the curious from finding thier crops. The black massers booby trap the ereas where thier alters are. And a year or two back a grown man, who looked to be of average intelligence strung a heavy steel cable betweeen two trees on a popular but illegal ATV and dirt biike trail on public land, at chest level. As far as I know he was never prosecuted.