You are looking at this from the wrong angle. It is extremely likely that this is not about CP at all, but that Google wanted an effective image censorship system. They realized that this may be hard to sell to the public, so they found CP as an easy solution. They can even use it for that only for the first few months (which will be almost invisible, as there cannot be a lot of CP accessible via Google, if there is anything at all...), then they an start to put in other pictures that are "undesirable", like pictures of political protests, police brutality, etc. And if anybody protests, they can just report them for searching CP. When the life of the one protesting has been ruined, they can just blame it on a "technical problem".
Quite ingenious, if utterly evil.