The really big collectors are, as far as I know, 100% against slabbing (except for Henry, of course). I'm also pretty sure that they would all buy a slabbed chip they needed and bust it out, if the price was right.

BTW, as long as the "whales" are opposed to slabbing, I don't see ICG as the threat that most do. Ironically, I think that ICG be beneficial in that it may become a top recruiter for the hobby.