Why would Google care is it is sued? The last time the authors' societies did that, it was converted to a class action (binding all authors, not just those that brought the action) and it now looks like the settlement will give Google preferential terms for digital reproduction of books forever.

Google must have be laughing at being sued by the photographer's society.

Google's attitude to copyright is to not care. This places the collection societies over a barrel (they are not going to condemn themselves to irrelevance by not doing a deal with Google. Or worse still, persisting with prosecution until Google is enjoined from ever distributing the society's material). Since the society's need to settle, Google has the negotiation whip hand.