> From my understanding, yes, it won't be possible to import data from 

> Wikipedia infoboxes etc. into a CC0 WikiData. (At least under European 

> Union law, where databases are protected by copyright)

is incorrect. A database right (http://en.wikipedia.org/wiki/Database_rights) is not a copyright, it is an independent property right granted on non-copyrightable materials. Since only the database as a whole achieves protection, not individual contributions, it is unclear to me whether Wikimedia Foundation can claim that right, or whether in the present situation of no-one owning the entire database, that right is actually unclaimable. 

However, I believe this is irrelevant. Creative Commons version 3 does include database rights for those localized licenses in legislations implementing database rights (e.g. http://creativecommons.org/licenses/by-sa/3.0/nl/legalcode http://creativecommons.org/licenses/by-sa/3.0/de/legalcode). They are included in the works, while at the same time, the license does waive any specific database rights to avoid database right proliferation.

Gregor