In gnome-control-center in Fedora 15, you could set a user's password to None and when that user would click his account in gdm, he would get logged in directly.

In Fedora 16, this doesn't seem to work anymore:
- when you exit and re-enter the users management dialog of gnome-control-center after applying this change, the account has been reset to inactive (instead of active with no password required)
- when trying to log in with gdm, that account requests a password (and entering nothing doesn't work).

Use case: single-user grandma who runs a limited user account and doesn't exactly need to go through gdm/user account auth.