Posted By:
JulieIn other words, I may be way off on this, but--
Wayne Varner's Shoebox Cards is also listed. I am therefore led to believe that the undersigned businesses accept cards graded by GAI (as well as other companies). Wayne V's stuff is pretty evenly split between GAI and PSA--with an occasional SGC thrown in. Lately, though, there have been more and more GAI.
So my guess is that GAI's list is not of people who use their services, excusively or otherwise, but of people who accewpt cards for their business from GAI--as well as other grading companies.
You'll notice that Mastronet is also listed. They do seem to have more stuff from PSA than anyone else...