As for the Z flag, my experience is that no one knows what it means, so everyone ignores it. YMMV...
Mike
It's only ignored until they check their scores at the end of the day. If the competitors won't take the time to understand how the game is played then they have to learn the rules the hard way. Far better to learn the lesson at a weekend regatta rather than a week long championship. Because the Z flag is initially ignored is not a reason to keep it rolled up on the deck in my opinion.
