As someone who has worked a lot in the criminal justice system, I see something missing there. There are a couple of other things most people would recognize as contributing factors. One is an awareness of problems within the institution before they become more severe. An effectively functioning complaints system will allow the administrators and staff in corrections to know of upcoming problems. This can also function as a release of pressure and help reduce levels of conflict and violence by providing an effective complaint procedure. With that context missing from your question, I worry about your focus on the vexatious complainants rather than on improving the system.
On March 13th, 2012. See this statement in context.