I'm probably talking to the wall but hey...
For the open seats at worlds, I don't think it makes sense for a 'jam the system' type of registration which is just an exercise in frustration. Why not do it like the various tech conferences that likewise have a high demand. Allow people to register via email, have a lottery and that's it. No sitting there stressed out over a payment system that can't take the load, or a website melting down.
Makes for a 'fair' system specially for those in out or where ever across the globe.
Thanks!