Remember Monday when I said that someone would suggest the students should've been armed at VT? Well sure enough, an otherwise smart guy I work with, who has an MBA and writes code for a living, said exactly that in an e-mail thread at work.
Now that we know more about the shooter, it's pretty clear to me that nothing could have prevented the outcome short of locking the guy up. Even then, that opens a debate about how to deal with mentally ill people, and I'd guess the vast majority of those people are able to function in society to some functional level. We can't lock them all up either.
I think Gonch put it best when he said shit happens, it's tragic, and there isn't much we can do about it.