Charter schools typically have an "at will" contract. This means you can be fired for any reason at any time. While this sounds reasonable to most people, things work slightly different in a school system. The union was the only thing that protected my job. I had a parent rage and complain about me and the supposedly awful thing I said to her darling daughter. The union stood in my corner and brought evidence forward that the mother made her false accusations when I was out for a week with the flu. The mother still thinks I drove in that week to torment her daughter.

If you are let go from a teaching job during the middle of the year, you are dead. There is no coming back from that. No one will ever hire you. You never know when an administrator or parent may have it in for you.

Here's an NPR article on how charter schools rarely serve special needs students: http://www.npr.org/2011/12/14/143659449/florida-charter-schools-failing-disabled-students