Thanks Matt, that's what I thought. The practical thing for port to do is gybe, but I doubt anyone would protest this after a finish. Most sailors think once you've touched the line, you're done, and are happy just to move on to the next race. Seems like only ROs and judges (and probably match racers) appreciate the full rule and definition.

Jake, it's because it's a mark, covered by RRS 18. Most likely, it's to add fairness and open options. Otherwise, everyone would approach on starboard, cutting out part of the racecourse.

Mike