The RYA don't encompass, promote single handed long distance yacht racing for the very same reasons.
As for the C mark rounding scenario if another boat had been adversely affected by the one making a complete hash of it then they could always apply for redress. However, if they luffed up without giving the boat in trouble enough time to react then they could be protested. In some cases they could also be luffing from behind which I think is still a no no?