I just had a very odd experience. I was running a kde session on machine a,
opened an ssh -Y connection to machine b, and ran a rhythmbox from there (to
test some statusicon stuff). I killed rhythmbox and went on to do something else.
When I came back after a while, I was surprised to find machine a locked,
by gnome-screensaver from machine b !

Quick analysis: running rhythmbox starts gnome-settings-daemon (for multimedia
key handling), which in turn starts gnome-screensaver (on the ssh-forwarded
display).

Ray and I think that the bug here is that activating gnome-settings-daemon has
the side-effect of starting gnome-screensaver. It should not do that, instead
gnome-screensaver should be a regular autostarted app.