Security issue? graphical logout doesn't close tty login
Ubuntu Studio (xubuntu) 13.10 64-bit
On a troubleshooting quest I created a new user with admin rights. After graphical login I opened a terminal through CTRL-ALT-F3. When finished I did ALT-F7 and logged out (power button, log out).
Then I logged in as my regular user and ran CTRL-ALT-F3 again. This opened the previous session, with the new user still logged in, active, and enabled to pass commands.
This behaviour was unexpected to me - I expected logout to close terminals as well - and looks like a possible security issue. Shouldn't (graphical) logout close all open sessions?