CHICAGO (CBS) — Mayor Rahm Emanuel is vigorously defending policies at the Noble Charter Schools where students are fined for what some parents say are minor infractions.

As WBBM Newsradio Political Editor Craig Dellimore reports, Mayor Emanuel acknowledges the Noble Street Charter Network issues demerits and subsequent detentions and fees to kids for such offenses as chewing gum, being tardy to class, or carrying a permanent marker.

LISTEN: WBBM Newsradio’s Political Editor Craig Dellimore reports

But while some parents of students at the schools complain, the mayor says most do not.

“Parents send their kids to Noble, which is a school of choice – that means parents can choose to do it – defended the policy at the school,” Emanuel said. “If they don’t want to do it, they don’t have to go there. They chose to go there.”

Mayor Emanuel says he is interested in results.

“Ninety percent graduation rate at Noble; citywide, 54,” he said.

Mayor Emanuel says he wants to give parents more choices like those at the Noble Street schools.

Since 2008, Noble Schools have collected more than $386,000 in fines and fees for behavior classes–including more than $188,000 last school year alone, CBS 2’s Mai Martinez reported earlier this week.

Students get demerits for an assortment of violations. Four demerits equal a detention, and a $5 fee to help cover the cost of staffing detention.

If a student gets 12 detentions, they have to take a $140 discipline course.

Protesters rallied outside the Chicago Public Schools headquarters downtown earlier this week, saying most low-income families just can’t afford that, and they fear with the success of Noble Schools, the fees could be adopted across the CPS system.

Protesters chanted: “Invest in us, stop arresting us.”

But school officials say students manage to go the entire year without getting a single demerit, so it’s possible never to receive a $5 fine.