From what I saw, it was so puffy and shifty, I think they were more focused on finding the next puff and staying in it than covering the guys behind them...
Been there, done that, every year at Wildcat and last year at Tradewinds there were a lot of puffs/shifts that would draw you away from covering.
It is possible to have too much of a lead. If boat speed isn't a problem, like someone mentioned earlier, cash in a little of that lead to cover cover cover so you can stay near the same wind system of your competition. Whether you cross the line with a 3 minute or a 3 second lead, it's still a win.
That gybe by Spithill (who was on starboard) to try and blanket NZ when NZ first got the lead baffled me. Even if they pulled that off and were able to blanket them, they wouldn't have been able to pass them since NZ was lower down the course and NZ would still have the inside track to get back to the mark. I believe they would have been better served to make NZ duck and carry that gybe out a short distance toward the middle and make the call for the gybe back for the layline (and hope to cross) or based on the available pressure / angle. NZ made a huge gain on that side so it shouldn't have been a horrible idea to go that way and hope you gained a couple of boat lengths.
