Several of the things inmates are allowed to do are actually privileges. There is no requirement that they be allowed to do them. Privileges are a tool the jail uses to help keep inmates under control. It is a valid non-violent method that works more often than not. When you have very little, what little you do have you do not want to lose. If inmates follow the regulations they are allowed to keep their privileges. Violations, depending on what the violation is and the degree it was done to, can get them taken away from an inmate.
Inmates on Disciplinary Detention can lose privileges such as: Match/Patch program, GED program, Art programs, Educational programs, telephone use, inmate to inmate visits, day room access, trustee status and more. The losses are usually not permanent except possibly the trustee status and there is a system in place for the inmates to file a grievance if they feel the disciplinary action is unjust.