Why are all criminals in prison bald?

It is a long-standing unwritten management rule for criminals to shave their heads. Because this is not only convenient for prison management (such as hygiene, preventing hiding things in hair), but also very easy to distinguish. Once the prisoner escapes from prison, even if the prisoner wears a wig in disguise, it is easy to identify and find the target during the arrest. I am afraid that the necessary measures taken at the beginning were based on this idea. Baldness, like serving a sentence, is a punishment for prisoners and warns them not to engage in criminal activities in the future. Humanistic care for prisoners is not reflected in whether they are bald or not, but in their reform activities. We should really care for them, purify their hearts, and help them reintegrate into society and start a new life. With the progress of judicial civilization, this traditional custom is gradually changing. Haikou, Shanghai and other places have abolished this hard and fast rule, and prisoners can keep a rigid position, which also reflects the humanization trend of prison management.