Samba 'homes' share and users randomly deciding to put capital letters in their usernames

I created a 'homes' share in Samba, tested, and then moved all our user profiles over to it.

[homes]
    comment = User Profiles
    path = /tank/users/%U
    valid users = %U
    browseable = no
    writable = yes
    hide dot files = yes

During testing I had no problems with my test profiles. I would sign in to Windows as 'aaron', and it would find my folder under /tank/users/aaron.

Then I moved it in to production and moved everyone over to the new server.

I immediately got calls from users that their desktops were gone. After some digging, I found that some users were signing in as 'JSmith' which Samba translated into looking for /tank/users/JSmith instead of /tank/users/jsmith. As a stop-gap, I simply renamed their folders to the case they were using to sign in.

But I still get sporadic calls from users who suddenly to decide to sign in as 'Jsmith' one day, 'JSmith' another day, 'jsmith' the following day, and even 'JSMITH' because they left their capslock on.

Digging through the samba docs, I don't see a way to force that path to be all lower-case regardless of what the user enters on the login screen.

Am I missing something? Seems like this would be a frequent problem for people hosting files on Samba.