Open the URL, I self-hosted a zip file with 9 photos so you don't have to visit a website that's filled with ads.
http://rentingcrisis.nz/forum/images/chalk/activism.zip
I wrote in 20 locations around riccarton and ilam. Most of my chalk was on riccarton road or perhaps 50 metres into a side street.
Please share this file.
In the Netherlands we have two categories of rental homes: social and "free".
Social ones have a rental price cap set by the government based on a point system (more points = higher max rent). These points are a reflection of the value given to living there. Dishwasher? That's a bunch of points, separate garden? More points. It's not perfect, but it's helping a whole bunch.
If your house is being rented for more than a certain amount per month, you're in the free section. No real requirements are present there. Renters still have very strong protections from landlord abuse through.
If you're to implement a cascading tax system which increases per house, the second group would be the one I'd target. Social housing isn't very profitable and is therefore mostly run by non-profits.