Stupidity - is it a crime?

Tina Griekspoor and her mother Evelyn Border have been very publicly shamed, after they stole £50 worth of giftcards from a nine-year-old girl on her birthday.
The two women, who spied the cards on a shelf after the child put them down to talk to a WalMart clerk, used the money on them to pay for their own goods.
However, instead of being sentenced to what would likely to have been jail time, Griekspoor and Border agreed to stand outside the Bedford County courthouse in Pennsylvania, U.S, wearing sandwich boards denoting their crime: "I stole from a 9-year-old on her birthday! Don't steal or this could happen to you!"
This got me thinking about the case of Philip Laing, a 19-year-old student from Macclesfield, who urinated over wreaths of poppies on a war memorial after getting stupendously drunk on a bar crawl and is now looking at a prison sentence.
I remember, quite visibly, many moons ago, a teacher of mine telling my class about the case of another young man, who had also gotten drunk, peeing in the street and getting arrested and imprisoned for indecent exposure. After his stint inside, he was, apparently, never the same.
Now, I in no way approve of what this young man did. However, I think that for a crime that most people could put down to sheer stupidity and a tremendous amount of booze, prison isn't the place for him. After already being splashed over the pages of the national papers, the humiliation he has suffered is, I feel, a more appropriate punishment.
Perhaps the UK should lead by the U.S's example and publicly shame, rather than imprison, people who have committed crimes such as these.