In the US, they should be installed on all retail bicycles at time of sale. This is covered by the Consumer Product Safety Commission. The only bicycles that are exempt are track and custom bicycles. There is nothing on the Federal level preventing people from removing reflectors, but they should have them at the time of sale. They can take the form of a reflective tire sidewall or rim. The CPSC is also the reason bicycles have the pie plate (dork disc).

Now, the OP is presumably referring to a New Zealand publication? I curious as to the details as well.