The two cases are here and here. If you go read these, you will see that I've replied with messages correcting them about what the name of the convention they attended was. I'm sure they won't be pleased by that -- after all, who cares, right?
Unfortunately, it's sort of my job (albeit unpaid) to care about this sort of thing.
I'm sure this has nothing to do with the management of WFC or any particular WFC committee. Heck, SFSFC is bidding to host a WFC, and we were the parent non-profit of the 1998 WFC. It's just a creeping erosion of the Worldcon service mark that I feel obliged to do my part to stop.