Betta Turn Rasta, Or His Dreads Are Hasta
New York prison rules states that male prisoners are only allowed to wear their hair in cornrows, going straight back. And they can't exceed the "natural hairline" in length.
Natural hairline means: "It means it can't extend the neck." Now, prisoners who claim Rastafarri as their religion are allowed in most cases to keep their locks. But even then there's a process to determine if it's genuine.