I have a problem with the wording on this page. First it is too weak ("...try to..", "...it never hurts to...") but more importantly, I think the exception for group shot is very bad: by explicitly saying that it's ok to take group shots without asking consent, we make it even more difficult for someone who doesn't want to be photographed to say so.
I was more expecting something along the lines of the CCC policy, which create a safe atmosphere where you can be confident that, as long as nobody asked you, you won't end up in a photograph on facebook or whatever. Here is how it is worded there:
Ask everybody in the picture if they agree to be photographed or filmed. It follows that shots from the stage into the audience and long shots in the hack center and the other public areas are not possible! Please note that we might ask photographers and film teams to leave if they don't behave accordingly.