An active shooter running around the UT campus and nearby areas in the last 60 days (he only shot himself, no other injuries)
Unfortunately, as you can't legally carry on a school (barring specific situations, e.g. locked in your car; permission to take it to a related class, etc.), this would have been a moot point.
wrs840, great testimony in that link. I particularly liked the "I'm not mad at the man, I'm not mad at the guns, I am mad at the legislature who made it illegal for me to defend myself or my family" as well as the "You say 'no legitimate sporting/hunting use', but that's not what 2A is about." She was a very smart woman.
Gauronga, very apt analogy about the seat belts and airbags. Although consider that a lot of people think "You're more likely to live if thrown from the car if it sets on fire" and "Airbags can break your neck".
I actually decided to carry (I've always been into guns) because of Security+. For those who don't know what that is, it is actually a CompTIA certification for computer technicians, with a focus on security (including physical security). One of the things in the book is formulae for finding out whether a security measure is cost effective, based on multiple factors (frequency of problem, loss per occurrence, cost of security measure). The way I figure it, for under $1000, I get - a home defense weapon (I have homeowner's and life insurance, but it can't protect information or give me a new life), a carry weapon (see life insurance), and a cool range toy. On the flip side, I could save less than a grand and possibly get killed.