In order to search visitors or staff prison officials should have at least how much evidence indicating misconduct (likely, the introduction of contraband) ?

The search of bags and pockets is a requirement for security reasons at prisons, prior to any contact a person has with someone they want to visit. This procedure is not a result of suspect or misconduct of visitors. The searches should always be done politely and in a respectful manner. But if some visitor breaks any of the prison visit rules or is a threat to prison security, this person may have their visit cut short.