Bug bags are not only for fight or flight, but rather any time you need to leave in a hurry.. Fire, flood... Um were in Oklahoma so tornadoes.
I guess a bug out bag would work great for Tornadoes....if you can find the bag afterward, and had a reason to "bug out". I'd rather hang around the place, looking for lost things, and guard what was left from possible looters than to grab my stuff and run off somewhere. Now if you're talking pre-storm, then I'll be more concerned about getting my kids into a shelter than having a bag full of stuff to pack with me. Try to keep flashlights, etc, in your shelter.