Ten charter high schools in Chicago have come up with a novel — and controversial — way to raise extra cash. The Noble Network of Charter Schools is now imposing fines on students who repeatedly break campus rules. Administrators at the network's schools, which Mayor Rahm Emanuel has praised as models of academic excellence, seem thrilled about the windfall, but parents aren't quite so happy. Here's what you should know:

How do the fines work?
Students get demerits for breaking school rules — four for having a cell phone, for example, and one for having their shoelaces untied, or failing to tuck their polo shirt into their uniform khakis. Any kid who piles up four demerits in a two-week period has to serve detention after school, which means forking over a $5 detention "admission" fee. Anyone who gets 12 detentions in a year has to attend a summer behavior class. Cost: $140.

Is this really necessary?
It certainly brings in much-needed money. The network raked in $190,000 from the fines last year. In part, the cash went toward defraying the cost of having to pay teachers to supervise the detention hall. But the money's not the main thing, says Noble founder and CEO Michael Milkie. This policy teaches discipline and helps keep the network's overwhelmingly poor, minority students focused on their studies. "[By] sweating the small stuff," he says, "we don't have issues with the big stuff."

Does it work?
Perhaps. At the very least, nobody can deny that Noble schools have high achievement levels. Noble's ACT scores are higher than the city average, and 90 percent of its graduates go on to college.

So what's the problem?
Noble is charging its mostly low-income students a hidden tax their families can't afford, say the Chicago Tribune, and "pushing these young people out of school" to boost test results. "Fining someone for having their shoelaces untied ... goes to harassment, not discipline," Julie Woestehoff, executive director of Parents United for Responsible Education, tells the Associated Press. Give me a break, says Susan Graybeal at Yahoo News. "It's called accountability, and it's how life works."

Sources: AP, Babble, Chicago Tribune, MSNBC, Yahoo News