Daylight, people go to find peace and walk on the grass
Night, da dudez go to find war, "easy" dough and to smoke some grass...
Except if:
Night, da pooleeze go to nab da dudez and get them in jail, and the people go there to find peace and walk on grass without trouble
Solution: Just have some guards stationed on the park at night, that solves all.
A decent park should have:
Monuments, benches, hippies(oops, wrong place man), some wandering mechants selling food(and catnip too

), lots of space for running, lots of flora, among other things.