I have to agree with graeme_p. Pedophiles are depressingly well connected via peer-to-peer networks which are hidden all sorts of ways from law enforcement. I was just reading that the FBI is begging lawmakers to update laws and give them more tools for tracking these people down, because it's just that difficult.
The pedophile rings that have been broken up so far are not relying on Google and Bing. If they were, they'd be much easier to catch.
If the SEs wanted to do this just on principle, I have no problem with that. But anyone claiming this like it's some big victory for law enforcement is being dangerously misleading. Almost to the point of helping the bad guys stay hidden.