In my college days I used to type up old federal court cases for electronic scanning. One case I came across involved a man who, as part of a "creative" sentence was instructed by the judge to wear a sign that read "I am a thief" (or some such; I can't remember the exact offense). He successfully challenged the the sentence on the grounds that no government entity can force a person to admit guilt to a crime, even if he's been found guilty in a court of law. To allow such a thing would mean that an individual could be coerced into a confession, or denied the ability to appeal. I'm not surprised that there aren't more such challenges, though. Most people, given a choice between wearing such a sign or serving a jail sentence would swallow their scruples and choose the former.
Being an idiot isn't a crime yet, though. ;-)
Interesting old job -- how long did you last typing those up?