"One must not put a loaded rifle on the stage if no one is thinking of firing it."
Anton Pavlovich Chekhov
Or in MMO terms, don't put in a ground-mounted cannon/laser-destructor/harpoon-gun, allow me operate, aim and fire it then give it nothing to hit but dirt. I'm looking at you, Warhammer Online.
If you're going to do it, do it like this.
(And yes, I did install FRAPS today and yes, I am learning how to use the YouTube account I've been neglecting for three years. So sue me).