You can thank the TSA for the secondary screening.
I really fail to understand how asking somebody whether they've packed their own bag and whether anybody else has touched my bag today ("yes multiple baggage handling staff at Wellington, Auckland domestic and Auckland international" seemed to be an answer he wasn't prepared for as he simply replied "oh") improves security. Given the calibre of the staff I'd highly doubt they've had anything other than pretty basic training for watching for abnormal behavior characteristics.