[Catalyst] logout and go back to previous session?

[Carl Johnstone]

> now. somebody else can use the same computer/browser to connect to his
> account - named, with full login/password things.
> so we create him a session (short term, only till the closing of browser).
>
> but. after this "named" user will logout, or close the browser and
> reopen - we should be able to go back to the previous "anonymous"
> user.

This doesn't make sense to me, before the named user logs in they'll be 
accessing the same anonymous session. Therefore you can't tell the 
difference between the two different users.

Carl