Comment 3 for bug 1267742

Marking this as security related for the moment.

Restarting a PC that will then be left at a login screen should not show the previous session.

"This bug is a security vulnerability: Please check this only if your bug report describes a behaviour that could be exploited to compromise your security or safety, as well as cause issues such as identity theft or "hi-jacking". " from https://help.ubuntu.com/community/ReportingBugs