Lockscreen bypass?

[klaus u schallhorn]

I have a somewhat unusual requirement for which I found no solution in the
FMs.

I need to share a 3/60 console between two people, one working on it a few
hours in the morning, the other in the afternoon. In between I want it to
run lockscreen [or something to that effect] to prevent the screen
contents to be burned into the hardware [;-)].

Is it possible for user A to run lockscreen and go home, while user B
later kills lockscreen and logs in as user B? I don't want to go over
there each time and enter user A's passwd just to do a decent logout.
Killing lockscreen remotely is ugly [and I haven't even tried this].

I offer eternal gratitude for any valid pointers.