I respectfully disagree. When I was younger I never really thought about checking such things. However, as I got older, and especially as we began having more mass shootings, I do a cursory check of my surroundings when I go into any facility now. Be it a restaurant, motel, concert arena, or movie theater. I'm not all that paranoid, but I figure I'm one step ahead if I already know which direction to go should I need to do so. It only takes a few minutes and it may save your life. I agree, all of those things should be 100% up to code, but, the fact is, that humans are fallible and screw up, therefore, I do a quick glance.
Edit: Again, I'm not laying blame to those living there or there for the concert, at their ages, I'd never thought it would happen either, but if anything can be learned from this, it would be to check your surroundings when you go somewhere. It may save your life.