Last year, Peter Dunne betrayed us all by agreeing to support John Key's spy bill. His vote was crucial in ensuring the bills passage - he was the government's majority in the second and third readings. His excuse was that Key had promised him that the definition of "private communication" - a crucial term in the bill, which apparently allowed the GCSB to spy on our metadata without any regulation or oversight - would be reviewed to ensure consistency and to ensure that metadata could not be captured.
But it turns out that Key lied: there will be no review. And thanks to that lie, we have a bill which enables NSA-style mass domestic spying.
The lesson should be obvious: do not accept such promises from Key (or any other politician) in future. Instead, demand that concessions are enacted in legislation immediately - and if they require policy work, then delay the legislation until that work is done. Statute or its bullshit. Its that simple.