Also, suggestions that we go out and try to buy up every plausible domain name in the form worldconYYYY.com|org|net|world|etc are not only expensive, but IMO relatively useless, given how easy it would be to evade the registration with something similar, e.g. worldcon-YYYY.com, etc.
I don't think we have a reasonable case to try to convince ICANN to prohibit any address that starts with "worldcon" anywhere in the world.