Yeah I'm guessing it had more to do with the card being dormant than anything to do with Gamestop. Especially with as shady as Ebay is, they probably have it in their agreement that any gift card not used in 90 days becomes "inactive" and you have to jump through hoops to reactivate, or something similar.
They did tie the $200 to my ebay account, so I did get the money back. No explanation as to why it was frozen.
I guess my original point was even if a GC shows $0 (on ebay at least) it may just be dormant or suspended. I wonder how many other companies do this. I know I have some old target GCs I bought just to get the collectible GC (like the pez dispensers, coins, etc) and I am wondering if I actually did clear them out or if they got the same treatment.
And to the other posters, I do normally immediately check the balance of GCs, but I was going to give this one as a gift. I gave the Southwest one as a gift too.