A single shot is unlikely to kill, and in these areas a snake can very quickly disappear into water or foliage. I doubt drones or night vision would help much for similar reasons - the issue lies as much in being able to reach the snakes as it does in being able to locate them. The Everglades are incredibly thick, a snake will easily outpace and hide from a human outside of roads. It does seem like there should be a better way than wrestling them but it's hard to say what that might be.