Comes back to: You can't prepare for everything.
^This. My Irish cousins had some pretty signature moves, and even then LE were unable to stop them. In a free society there is risk, we just have to live with that fact....
OR, we can go this way at large group events, including the movies...
1) Be happy wearing paper overalls, because that is what is issued at the door. You could have anything in your clothes.
2) Do the best to enjoy your cavity search. It's uglier from where we stand.
3) Bringing purses, bags, wallets your CCW? Nope, that ain't happening.
4) Leave you cellphone in the car, because otherwise we're confiscating it on the way in. Can't have you detonating bombs or calling others in the terrorist cell. Just in case, we've set up high power jammers, too.
5) We consider you ALL suspects. Get used to it.
Yes, I know I have taken this to what we normal folks consider extremes, but there are some who think that risk is to be eliminated at all costs. They would take us a good way down that road.