I love stuff like this...you could even leave an old reel on the rod, wind a lil of the line on and make it adjustable to different dockings if need be...
Good find, Skools
RB, the only reason I can think of for crossed lines is they provide additional length for the lines to stretch and absorb the shock when quickly pulled tight by a heavy boat...short tie-offs from boat cleat directly to dock cleat would have a greater tendancy to fail...