No one ever accused the slabbers of doing anything illegal.
The bottom line is that the service they offer benefits only one party, the slabbing company.
It has been stated numerous times that slabbing only adds to the cost, NOT to the value. They offer no warranty, refuse to disclose who their experts are and do not have any acceptable grading system.

Selling pornography is also legal however you wouldn't want to have it sold in your children's schools. You want to sell slabbed chips, you want to buy slabbed chips help yourself, but don't do it in my backyard.

BTW do you consider a growing list of 400 to be a FEW people