Board Thread:News and Announcements/@comment-24567267-20140217234910/@comment-961279-20140223165437

Access to Checkuser is reserved for Wikia staff because it reveals the IP addresses used by the account and provides other private information. It can be misused, so they are very careful about who has access to it.

There are other ways to connect accounts without having access to Checkuser. Just looking at the edits will often reveal patterns and phrases that will allow you to say that account B is run by the same person as account A with a fair amount of certainty.