Keep in mind that it really takes very little tyranny exerted over their characters to drive most players to violence so there is no need to over do it.
I developed such a state on the granny and librarian model. There was no need to have Paladins on every corner, instead all "improper" actions were immediately corrected with lectures and improper speech met with a loud "Shush". If the players insisted on trying to shout down someone the NPCs would join in song to drown them out. Violence would finally bring the paladins and clerics to drag the miscreants off to rehabilitation.
Of course not everyone can be so pure, it just takes some work to find the hidden underbelly of such a society.
I developed such a state on the granny and librarian model. There was no need to have Paladins on every corner, instead all "improper" actions were immediately corrected with lectures and improper speech met with a loud "Shush". If the players insisted on trying to shout down someone the NPCs would join in song to drown them out. Violence would finally bring the paladins and clerics to drag the miscreants off to rehabilitation.
Of course not everyone can be so pure, it just takes some work to find the hidden underbelly of such a society.