I wasn't there for the protest but I did discuss it with them prior and I think there was an aha moment when I mentioned it. That's when I discovered that they had been setting to the left in response to a complaint that setting a shortened course at a mark favors the boats to the side on which the line was set (thinking the sailors would need to round the mark before finishing).

I'm still not sure how the line can favor those to the right unless it is set really long and skewed heavily to opposite side from the mark. It's either that or someone was really out of racing position and not optimized to sail to the mark to begin with.

I think the correct method is to set the finish line to the right of the mark (as viewed while approaching it from the course), the line be as short as reasonable (3-4 boat lengths in a 12 boat fleet) but drop the line back to skew it slightly to favor the mark end but not so much that there is any question as to what side of the line is facing the direction of the last mark.