Was it the Ansett rep's applying the Borax or others ??
I think you may find things have changed a little at NZALPA. Some may say they are a bit soft now !!!... but I agree negotiation is preferable to war.
At the end of the day, in NZ one has the right to withdraw (or not) ones labour if required (never an enjoyable experience, which may explain the high emotions/threats at such times)
However if you belong to a union, ultimately you must be prepared to stand up for youself on the picket line or face the concessionary slide (see the current Oz situation) that will inevitably come.
The Company has the gold, you have the labour, both have what the other wants.... a balance will be found or all concerned will lose. Airline managment understand this better than anyone
I tend to think a "work to rule" is a waste of time as it can become messy.... induviduals can be targeted, and I'm not sure its a legal form of industrial action.