The problem there isn't the slab, its the way the chips were released.

Although I am against slabbing. Here is a link to an article were a coin slabbing service was able to notify bidders on a high end coin that it was in fact a fake. This ultimately lead to an indictment of the scammer.

http://dailynews.yahoo.com/h/ao/20001221/cr/woman_indicted_in_ebay_coin_scam_1.html