For about 3-4000 pages? Yes, I could do a cross-file search/replace with a perl script but haha, I am a conscientious objector of sorts, I don't see why we Pinterest puts the onus on all of us to OPT OUT when we ought to OPT IN instead.
Sure, we can do this now for Pinterest, but do we want to do this for every individual Pinterest clone wannabe in the future? NO.
Further, I hear that after people get the warning they can pin anyway, but I didn't verify this personally. Even if it worked, the message that pops up encourages visitors to write to the webmaster to question them. Not only are we hassled if we want to opt out, but even if we opt out, visitors are encouraged to still hassle us. ;-)
In a perfect world, Pinterest should show thumbnail-size images only. No one could complain, thumbnails have been legally deemed to be fair use already.
Why can't they just use thumbnails. PROBLEM SOLVED for everyone, Pinterest users are happy, Pinterest is happy, we're happy.