This is a conversation I have with people using Automated Starting Systems like RaceSense. The proper move would be to abandon, not General Recall as you've identified the boats. It would be reasonable to abandon for a reason affecting the fairness of the racing. Now, to your question about redress, I think it's probably a high bar to get redress. If they would have otherwise abandoned, has your score been made worse than if they did the proper signal of abandon? If yes, should they abandon the race and if they do, does that help your score? It's a grey area, but I think recognizing as a sailor that while they made the wrong signal, the race was still going to end is the healthy and happy answer. 

But, unless I am misreading the original post, the “restricted finish” in this case is 2/3 of the way up the course and nowhere near the starting area. The only boats playing in that area are the 18s and the H16s would only be there when finishing. So, again, I’ll ask, what issue are we trying to resolve by restricting this finish?

Agree.  As long as it's getting our of RRoS ok.

Draftable has a button to download the compared version.

RRS 63.5(a) requires protest committees to find facts 'based on the balance of probabilities (unless an applicable rule requires otherwise)'.

Finding fault of a boat’s own is a conclusion rather than a fact, so it's a matter fo  logical reasoning and judgemt by the protest committee, but, as fa  as it's relevant, I can't see any reason to depart from balance of probabilities.

Maybe it would help the discussion along if you pitched up a concrete example where you would be uncomfortable with BoP.