As you are fond of pointing out, without a license, you have no license to use the IP. If Medievia has no license to use Diku, for instance, because it allegedly doesn't conform to the available license requirements, then pick-a-Dragonball-Z mud also doesn't have a license, since there is no license available.
Ethically, I believe it's completely on the shoulders of the entity using the IP to gain explicit permission before doing so. Anything less is both prosecutable under the laws of virtually all western countries, and disrespectful of the IP owner to boot.
--matt
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