"There are things called enhancement fees," Attorney Tom Gonzalez said. "And there is a question that is not always clear of the line between when an enhancement fee becomes tuition, and when it is mandatory as opposed to not, when it's billed as opposed to solicited."
The line can seem hazy, he said, "especially since it seems that an awful lot of charters are pushing up against that line as hard as they can and are, in fact, seeking those funds from a variety of sources through an awful lot of coercion." http://www.tampabay.com/news/education/k12/hillsborough-officials-say-charter-schools-walk-fine-line-between-fees-and/2139421
How are charter schools public schools again? The answer is they are not but saying so gives the privatization crowd some cover. What they are is publicly funded private schools designed not to enhance education outcomes but to make a buck.