I've just emailed John Key. Here's what I said:
Dear Mr Key
I am writing to thank you for your determined stand on the issue of child "discipline" and for refusing to repeal or alter the current law. I imagine that you are likely to get many more messages attacking this stand than supporting it. But it is very heartening to see you refusing to bow to pressure from those who insist that we should reinstate the right to hit children - and thereby reopen the loophole which, in the past, allowed some seriously abusive adults to escape conviction. Your support for Sue Bradford's Bill in the House was admirable, and so is your current stance.
It would be a good idea if lots of people who support the legislation write in - Key and National are bound to be getting gazillions of messages attacking it. They need to know that they are not only doing the right thing, but that despite the referendum, there is plenty of support for retaining the law out there.