NZ does release seats in C and I have snagged a couple and helped some friends grab some as well, all within the past three months.

As for the post about UA not having seats available to SYD is just plain wrong -- and not particularly helpful for folks turning here for advice. A quick dummy booking on UA.com has just show N9 on three outbound (R2, R2, & R1) and N9 and N8 (R0 and R2) on two returns. This was just on a randomly selected two week span in March.

Sheesh...