No, that's not correct at all.
g-s-d/u-s-d do not run in Xubuntu, however, they do run in the greeter
if the greeter is unity-greeter. They exit before Xubuntu desktop starts
up, but at that point they have already ruined the monitor
configuration.
Since they do not run in Xubuntu, there is no wa
g-s-d/u-s-d shouldn't be running in xubuntu either no?
Renaming that bug, it's a feature request for the settings code to
detect nvidia custom configs and bail out of doing its work in those
case.
It would be better if nvidia users would use the standard interface for
their configuration though (