If it's voluntary, that would be a problem, yes. Though I suppose then you could point out that nobody in CG signed up for it, and that's a red flag. Why not? Are they not diligent and trusted campaigners?
I agree they should make it mandatory as a condition of using IGG, but I dunno if they are interested in going that far.
One of the reasons why I've long suspected IGG never cracked down on this crap is, at the end of the day, they're making money off of CG rubes too. Arguing ethics in the face of money to a corporation is never easy.