Strictly controled population.
No weapons allowed of any kind. Except of course for the police
LOTS of police/Guards to the ratio of less than 5:1 (in the US public it's something like 390:1)
To enter fantasyland you are subject to strict searches by guards.
Frequent serches of all areas of fantasyland for weapons/contraband.
Frequent serches of all people in fantasyland for weapons/contraband.
Video monitoring of all areas of fantasyland
Materials that could be made into weapons is severly resticted/controlled (metal, tools, ect) and posession of which is grounds for punishment.
OH WAIT fantasyland exists!
It's called the Prision system. It has a population of 2.25 million+ adults.
There are still frequent stabbings/murders
They still find weapons including homemade knives and even guns
They still find guns smuggled in somehow from outside
They still have a PROBLEM with illegal drugs that are smuggled in from outside.
HEY LEFTISTS to join your ideal society just commit a few felonies!