Server :: Uppercase Usernames In / Etc / Sudoers Triggers Warnings

We're syncing users from Active Directory over to our linux LDAP server (Red Hat Directory Server). The user names on the AD side are all written in uppcase letters, which is the company policy.The uppername usernames causes problems when setting up /etc/sudoers, since uppercase words are interpreted as aliases. For example, if I add user KENNETH to a User_Alias (i.e. something like "User_Alias ADMINS = KENNETH"), I will get a warning from visudo which expects KENNETH to be an alias and thus not a username. Despite the warning, sudo does seem to work correctly. But is there a way to tell visudo or sudo that usernames are uppercase, and should not trigger a warning? Or are there other ways to go about this sort of thing?