Hi Often1.
Thanks for the updates re DOT not enforcing. In NZ many people pay directly for Air NZ transactions ( as the charge for using a CC can add some $$ to the price). We use something called POLI which is essentially a direct transfer from your bank account to Air NZ's - hence no chargeback option. The other issue is the time allowing for CC chargebacks this side of the planet appears fairly restricted - about 2 months in most cases with ' exceptions' made for longer periods at the discretion of the card issuer.
So if they have bought and paid for the tickets in the last 4 months + then they first have to convince their CC issuer ( often a bank) to actually take up the option in the first place.
So, even with a good number of DOT complaints from this side of the planet, Air NZ can continue to operate as they currently do and apply a different view to refunds.