I'm perfectly fine with this, after all they have little choice because of the result from the Getty case, but now that option is gone they need to crack down on sites presenting different images when referred directly from Google than they present more generally: presenting an unaltered image to Google and a heavily watermarked one otherwise for instance, or sometimes the destination page redirecting off to something else if your request doesn't include a Google referrer or agent-string. These things are already against Google's policy and is basically the destination site being dishonest to the user (drawing people away from sites with the same content really but don't pretend to offer something else freely).