Advice?

I'm just finishing up my vid for the Vividcon premiere show, and it's a movie vid, to a film that relies pretty heavily on its plot twists. It's not M. Night Shyamalan, but same sort of issues; part of the movie's concept is the mystery of what's going on.

I've already tested it out (accidentally, and thank goodness she didn't mind) on a friend who hasn't seen the film, and am fairly confident that I haven't given away all the plotpoints, but it's still spoileriffic, by nature.

So, for the vidshow, given that I won't have the option of a neat little summary on my webpage to warn the spoiler-averse to rent the movie first, would it be a kindness to have a pre-vid "Spoiler Warning! If you haven't seen the film and you don't like spoilers, now would be a good time to...er...close your eyes..." title? Or do you think it would distract from the vid itself or annoy viewers/VJ's?