Hubby and I have discussed this alot. We keep the carriers out and handy - mostly in the CatRoom and the tribe sleep in them sometimes. And we make sure there aren't hiding places that we don't have access to in case we have to search & rescue for a scared cat. In our old house in CT. the guys would get up into the basement rafters and goof around or go there if someone new came to the house to visit. I knew that would be a preferred hiding place in case of a fire, so we finally blocked off access to the rafters.
Our house in WA. doesn't have a basement and it would be much easier to find everyone in case of emergency. I would LOVE to devise some kind of automatic escape window/hatch that would only open in case of fire and would let them out into an enlcosure away from the house. Pretty high tech, I know, but I worry most about a fire happening when I'm not at home.
Good thread for thought.