If the staff members know that a drill isn't real they propably wouldn't put as much effort into carrying it out. I know that at school when you knew that a fire alarm was just a drill you just wandered out and talked and really didn't make much effort. Obviously you would try harder somewhere like camp but you can only really see how well an emergency protocol works by actually carrying it out.
I didn't mean when I posted before that the campers were all panicked about the situation. I was just commenting that there was mass hysteria due to seeing a mouse rather than the fact that we were doing a tornado drill.