And again, allow me to preface this with a statement that while I am a member of the Slab-Free Chapter (Club) I am NOT a spokesperson for the Club, or the Officers. Having said that, it is my understanding that one of the most significant aspects of anti-slabbing, is that the grading of a chip is something that any collector can perform with a reasonable degree of accuracy and compentcy. Moreover, the chip manufacturing process is nowhere near the tolerences used in coin minting and modern sport card printing. Furthermore, a handled chip (even one that has been briefly in-play, Bud Jones CICs come to mind) can still be graded as NEW. And lastly, there is a great deal of distrust of "professional" grading services, as their guarantees, competence and reliability means absolutely nothing! Those services are viewed as just siphoning off a percentage of the pool of resources available for in the pursuit of the hobby.
Well, enough for now (from me anyway) but there is a great deal more to become aware on this subject.
I thank you for your interest in the subject. The Slab-Free Club is very focused on awareness and education on this subject.
Jim