Every charter school that incorporates has to declare who "members" of their corporation are. Some charter schools choose the parents of all currently enrolled students. Others have just the board be the members, particularly if it is a board of community members or a school run by a management company.
Members typically have voting rights. They usually cast their vote at the annual meeting, which is oftentimes in May for charter schools.
The members determine who holds the charter, or who really has the authority in a charter school. When problems arise at a charter school, the first thing parents should investigate is the school's bylaws.
The Articles of Incorporation are online on the Secretary of State's website. There's a searchable database and so it's easy to find out what corporate documents a charter school has filed. Sometimes the bylaws are also on this site, but most often bylaws are obtained through the school's front office. If access is readily provided, an Open Records Request should be filed. This means that by putting in writing that you want a copy of the bylaws, you must be given them within three business days.
There is no right or wrong way to decide who should be the members of a charter school. There are pros and cons to each scenario. But if someone wants to know where the "power" lies in a charter school: check the bylaws to find out who the "members" are.