"Even diamonds are certified from grading companies."

Certified as what? The only thing certifired is they will hoard the supply and keep the prices high. Diamonds would be worthless if the big guys would let the supply flow.

Yes slabbers are banned from the convention.
Maybe you should read some of the articles on slabree.com.

You are welcome to your opinions but slabs won't fly with most of us. Many of us raised $1,000's to fight them and we still have enough left to fight again.
Gene Trimble, VP of the Slabfree Club.