LinuxBSDos.com posted a tutorial about disabling guest session and create user accounts in Linux Mint 12

Linux Mint 12 is the latest release of the Ubuntu Desktop-based branch of Linux Mint. This release comes with several desktop options, a few screen shots of which have been posted here.

By default, Linux Mint 12 ships with a guest session enabled, so a password-less access to the system is possible from the login screen to anybody with physical access to a Linux Mint 12-powered computer. If you do not want that level of openness on your computer, this tutorial will show you how to disable that guest session, and also how to create additional user accounts on the system.

  Disable guest session and create user accounts in Linux Mint 12