Yes this comes in handy if you have two users sharing one box.
From live cd:
#init 3
#su knoppix
$ su
# startx $(which fluxbox) -- :1
A new Xsession using FLuxbox is started on screen 1.
Use Alt +F4/F5 (from cd) and Alt + F6/F7 (hdd install)
to toggle back and forth from screen 0 and 1
You can simply toggle to another VT w/ CTRL+ALT+F2 (for example) and do the same but do it as USER! not root.
Yes this comes in handy if you have two users sharing one box.

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