User blog comment:Dopp/Technical Update: April 10, 2012/@comment-4668895-20120410214849/@comment-4668895-20120410215314

That is incorrect. Administrators can add chatmod and banned from chat, and revoke their own administrator rights. Check Special:ListGroupRights. On some wikis, they can add more user groups. You may test this on a wiki where you are only an administrator.