The Un-exhibit

I wonder what would happen if I created an installation that was only described in a press conference and never seen. I wonder if i could obscure a video of the installation with a time stamped blank screen, and submit that at a press conference as proof of the installation. What would that say about video as art? Would the described work be diminished if it were never seen, only described? Can the same be said of a video of a body of video or film work?