Every kid growing up in the 1950s and 1960s played with toy guns, many of which looked like the real thing. The toy commercials of the era advertised these plastic replicas to millions of children with little or no ill effect,
I graduated from high school in 1968. There were some problem students. I do remember a student who robbed a bank during lunch and hid the money in his locker, but that was the rare exception. It was big news at the time because it was so out of the ordinary.
There were fights and petty thievery. The perpetrators were dealt with swiftly by the administration without having to worry that their parents would hire a lawyer and sue the school. There were no metal detectors. Lots of kids carried pocket knives.