On my network when a user is auto-logged-out, this feature seems to just activate fast-user-switching, Is that what it is supposed to do?
I am talking about the setting, as seen below in El Capitain, from
System Preferences, and you can also access this setting with profiles/mdm for example from the Profile Manager (formerly Workgroup Manager). I have this disabled in both the local system and the profiles assigned to both the devices and user-groups.
I've also seen the same proposed issue in Yosemite. This is annoying because when users don't logout, the system seems to go back to the login screen without clearing the RAM, possibly also locking files that are in use, etc.; creating a truly slow, buggy machine.