I think these minivans is a rational and smart move (amoral, but that's another story). The protest is snowballing and there's not enough police-like forces that blindly support the current regime. The administration understands that victory loves preparation and starts preparing now: they normalize the minivans, so people get used to them and won't question this later when millions of such minivans show up on streets. Generic outfit and lack of ID allows to hire just about anyone to work as a police-like force. My bet is that "the minivans force" will get out of control once they realise that nobody is looking after them. On a side note, I know that many rich and wealthy people have expressed a sudden interest to spend an extended vacation in new Zealand a few month ago.