People can roll their eyes at metal detectors and bag checks- but I agree, better than nothing.
The one thing no one can roll their eyes at? Working dogs. The best and most effective deterrent would be 4-5 bomb and gunpowder dogs spread out able to sniff nearly every person.
Some might think there would be difficulty with the loads of kids; But unlike “therapy dogs”, these dogs are rarely distracted by children, eye contact, etc.
When there are elevated threat levels, dogs often work the security line at airports more and every single guest gets a nose tap by the dog.
If you had a bomb or gun, and you saw dogs tapping every person- think you’d try to sneak it in? Negative.