This is specifically for photos which have already been made public.
As for the general issue: its up to the photographers. They don’t work for NZLARPS, we don’t own their photos, and we can’t dictate to them where they post them. It also means that specific privacy concerns are largely their problem, not ours (though GMs should be warning people that they may be photographed and that they should talk to the photographers if required).
In my experience, the photographers are already on top of these issues. They don’t post photos which make people look bad, will take stuff down on request, will avoid photographing you if you ask them to, and seek consent for wider republication. That’s not the same as getting explicit consent from everyone to post their photos online though, which is why a standard notice on signup forms is required.