Do you mean these people have handed in notices or are planning on quitting in the next day or so? Or do you mean these people are considering quitting if google doesn't change its ways? Or do you mean "Some people I know are saying that they will quit" but have no short term plan for actually quitting?
Quitting a job over an ethical issue doesn't take long. It goes like this: "I quit!"
And then, those people are no longer 'quitting' but now have become 'have quit.'
Try just going to eat at the Pho place across the street from Google in Boulder sometime, you'll hear people openly complaining about Sundar and Susan and chatting about their latest projects at full volume without a care in the world.
Anyways, we'll see what happens, if the company doesn't give in perhaps we will see some more "why I quit Google" blogs down the road.