Not at all. vbWiki doesn't modify the wiki database in any way.
All users created in vBulletin are created in MediaWiki (the first time the user visits the wiki).
vbWiki also updates the user's e-mail address, whether the user's e-mail is authenticated, language settings, etc.
The only changes you would see if you
disable vbWiki are:
- users with special characters in their name will now have to use their 'MediaWiki usernames' (in the example above ElfMage-45
- passwords are not synchronized.
vbWiki doesn't update the passwords in the Wiki DB because it doesn't need them, since all authentication goes through vBulletin's user DB.
However we could add this to vbWiki to be ready for the extremely far fetched possibility that you would want to uninstall vbWiki ...