I'm curious as to what they would have done if one of them actually did find a weapon let alone someone deranged.
Die. They would die. I don't know why trained, armed security isn't standard in all large venues these days. Probably money and politics.
You do realize that cell phones didn't always exist, and people still managed to survive?
What is your point? A lot of things didn't used to exist and yet enough people to survived their non-existence to continue to life of the species. That doesn't mean it is smart to get rid of all those things.
For every problem there is one solution which is simple, neat, and wrong. -- H. L. Mencken