Why not enforce a city curfew?

I just finished reading an article about ESL enforcing a 10 p.m. curfew do to a recent violent week. I now find my self wondering why more cities do not actively enforce curfews? 

I believe most cities have a curfew on the books but you never hear of it being enforced.  Is this another rule that we have, just to  have? What would it hurt to enforce the curfew?  Parents have nothing to be concerned with as long as their children are really where they are supposed to be right?

Police often feel as if their hands are tied when dealing with youth. Wouldn't a curfew enforcement untie those hands a little? Now some might say that curfew enforcement would be a waste of time but is it really? 

What good is happening late at night? Wouldn't it be worth it if it kept one child from over dosing? Wouldn't you think it was worth it if it was your car that wasn't broken into? Wouldn't a parent rather get called to come to the station and pay a fine than go to the hospital and pay for a funeral?  I don't think that we should wait until we are in desperate need of curfew enforcement to enforce curfew. Wouldn't it be nice to be proactive for a change instead of reactive. 

There has already been a very steady rise in teen crime and drug use in St. Charles County, how bad does law enforcement want it to get?