I would think that the NZ Commerce Commission will take a very dim view of this - I am sure that in previous similar cases they have ruled that the onus is on the airlines website to get the information correct and that if they advertise incorrect fares they must honour any which have been booked and paid in full - I suspect that the negative publicity plus fines will outweigh the losses that would have been incurred in honouring the 100 or so tickets sold