I don't want to disable my screensaver cos I like it but, on the other hand, I don't like it so much that I want it arriving during a movie.
If, like me, you are running xscreensaver then 'xscreensaver-command -prefs' will allow you to configure it or even disable it.
I don't want to disable it I just want to stop its anomalous behaviour of popping in while I'm watching something salacious on vlc.
Will Gerald's solution do that I wonder.