Why can't family members in criminal detention visit?

1, administrative detention, judicial detention, family members can make an appointment in advance to visit within the specified time in the detention center. You can bring necessary daily necessities, clothes and food (subject to the inspection and consent of the police in the detention center) when visiting, and other things may not be given to the punished person. 2. Criminal detention, during which close relatives are not allowed to visit, but lawyers can visit as defense agents. When a lawyer meets a criminal suspect in custody, the investigation organ may send personnel to be present according to the circumstances and needs of the case. When a lawyer meets a detainee, he shall also hold a lawyer's practice certificate, a law firm certificate, a power of attorney or a letter of legal aid. According to Article 28 of the Regulations on Detention Centers, criminals can communicate and meet with their close relatives with the consent of the case-handling organ and the approval of the public security organ during their detention.