I do this for some of the youthful offenders in our community. It costs the library more in lost hours of work from me than we gain from their "free" labor.

-They require intense supervision, because they are non-cooperative generally -- that's why they're there -- and don't do the jobs properly.
-They tend to be erratic in their attendance, and because I have no control over their movements and sometimes have very sketchy contact information (I won't do business with one county's probation office anymore because of this), I have to make two schedules: one in case they show up, and one in case they don't. The jobs all have to be done regardless.
-Their little posses of unindicted co-conspirators come to the building and set up social clubs, which I have to break up several times a week because they disrupt business.
-Booting people means I wind up spending a couple of hours on the phone to the PO, who doesn't want to have to find another placement, and to the parent, who is outraged that the kid was kicked out of the public library. (I have had frequent conversations with people who don't understand that "public" doesn't mean they get to do whatever they want. This is true of parks, too, but parks are even harder to police.) Sometimes this involves vandalism and harrassment by the kid him- or herself, not only directed at me, but at other members of the staff and the building itself.

The only positive "community service" experiences I have had have been with people who are assigned because of a DUI, but are basically good citizens, and truants who stay home because of depression or family problems. Oh, and two kids who were caught in two separate incidents by the "zero tolerance" dragnet. They had both gone to the office voluntarily to report that they had forgotten to leave an object home, and to ask the office to keep it until a parent could come pick it up. (One was a pen knife; the other was a box-cutter the kid used at work.) Nothing like suspending and arresting a kid for honesty. grrr

The rest have been less than helpful, to put it mildly.

My heart goes out to overworked park employees who have to supervise criminals working off their sentence. Unless the work assignment comes with a supervisor dedicated to the workers, and unless there is some way to guarantee they actually show up, it will only cause problems.

It may be that the reason more people go to prison is because there are fewer and fewer organizations willing to take people on work-release because of experiences such as mine, though I have no numbers to support this suggestion. Bear in mind that most eligible convicts are not nearly like Martha Stewart, and even she has been accused of assault by a neighbor in the past.

Who here would like to have a convicted criminal doing light housekeeping in their workplace? Do I see any hands?