I wonder how that ruling helps to stop future collisions, the judges must have said oh black tricked yellow by giving some room therefore it was okay for yellow to continue on port, even though if yellow had tacked early enough black would have held it's line on starboard and no collision.
No rule requires one boat to anticipate what the other boat might do. This boils down to "did yellow react fast enough" to how black physically presented his boat to him. I think yellow eased their main and started to bear away pretty fast once it became clear that black wasn't actually tacking. You could argue that yellow should have tacked but I would counter with the fact that it's a crewed boat and it takes coordination to tack a boat without throwing people in the water. I think the attempted duck was a reasonable action...he just wasn't allowed enough time or opportunity to do so.
