That is really neat. It makes sense because the dolphins love to cruise behind a boat that is just under the speed of rotation for the hull. The same speed for a good surf wake. I guess because the dolphin are found more in the deep, fast current, well traveled passes is why we don't see more of this. I am always looking for a quiet hidy hole and so, not many dolphin there.
I did run a boarder right over a manatee once a few years ago... LOL those things move pretty fast when they get Ollied!