Honestly, I'm not completely against that sort of idea. I don't think it would work in practice, and I know parents would be pissed, but when you get right down to it, so many kids lack a work ethic. Have you seen the snotty rich white kids working retail these days? It's a bit sickening to see the disdain these people have for me after asking them to, you know, do their job.
But in this day and age, where everyone wants kids to go to College despite a severe lack of jobs for those with degrees, being a Janitor (or any type of blue collar) is looked down upon, so no one will allow it. Hell, giving kids jobs as janitors (around the 14 or so age range) might actually teach them that, hey, SOMEONE has to clean up your mess, and teach them some level of respect.
But again, it's all nice in theory. In practice, it would probably be a disaster.